Captain Jack chases a Weevil through the back streets of Cardiff and eventually traps it in a dead end. The creature turns to face him and Jack produces an anti-Weevil spray and some hand-clamps and suggests it comes quietly and make it easy for both of them. The creature is backed into a corner and has no choice but to attack - and the two of them throw each other around the alley. The Weevil manages to get the better of Jack and leaves him with a bloodied claw mark across his chest. Not for the first time, he regrets giving his team the night off…

Gwen is having a meal in a restaurant with Rhys - but he notices she’s not particularly enjoying herself. He’s been trying to engage her in conversation about the food and a previous trip they both made to Paris, but it’s clear her thoughts are elsewhere. In mid sentence he stops and demands to know why she looks like she’d rather be somewhere else. He’s realised this is becoming the norm - he’ll be talking away and when he looks up, her mind is absent. He wants to know what’s happening to their relationship and she apologises, but before he can get any more answers from her, he spots the Weevil racing across the road behind her. Gwen turns round just in time to see Jack arrive, searching for his prey. Jack joins them at the table and introduces himself to Rhys for the first time, but Gwen is worried about the claw marks on his chest. Jack tells Rhys it’s an emergency and promises he’ll have Gwen back in time for dessert, but Rhys becomes furious and demands that Gwen sit back down. She’s shocked by his anger and tells him never to speak to her like that again. He reminds her that she promised him one night off and orders her not to go with Jack, but without saying another word she races off after Jack.

Gwen catches up with Jack in one of the back streets. He apologises for cutting in on her night, but explains that he’s been having trouble with this particular Weevil. She dismisses Rhys and is sure he’ll get over it, but Jack reminds her that she’d promised him she’d keep a hold of her outside life and not let it drift. Jack picks up a signal from the Weevil and they head for a nearby multi-storey car park. They arrive and find the location apparently empty. They cautiously search between the parked cars and suddenly the Weevil emerges from cover and races off. They give chase, but before they can catch up with it, a large unmarked white van screeches round the corner and some masked men leap out. They attack the Weevil with electric prods and drag the struggling creature into the back. Jack and Gwen come round the corner and call to the men to stop what they’re doing, but the leader of the masked men just nods at them and the van drives away before they can stop it.

Back at the Hub, Jack lists the questions that have arisen from their recent encounter. Firstly, since when did anyone else know about the existence of the Weevils? Secondly, have they done this before and if so, how come he didn’t know about it? Thirdly, what do they want with them anyway? Ianto has done some research and although it may not be connected, there are reports of a recent surge of injuries at the hospital that include chunks taken out of legs and arms, and deep wounds to people’s backs and stomachs. It appears they have an increase in Weevil attacks to contend with too. He also notes that the anti-Weevil spray doesn’t seem to work any more, so they’re becoming immune to it, either through mutation or evolution. Tosh has run a trace on the licence number of the van, but it was fake. There are 2,500 vans of that description in the Cardiff area alone and that number doubles if the range is increased to 40 miles, so instead she’s trying to follow the van’s route via the city’s CCTV cameras.

In the boardroom, Gwen tries to call Rhys. She’s left three messages for him already and she tells him she has thousands of excuses, but none of them are good enough. She tells him things have gotten away from her a bit lately, but it’s the job that’s to blame as it never lets up. She tells him she’ll see him later, but she’s not sure what time. At their home, Rhys is silently listening to her message. He’s about to pick up the phone to speak to her, but when she says she has some work to finish off first, he changes his mind and lets her hang up. Then he deletes the message.

At a crowded bar in the city centre, Owen’s phone keeps ringing, but he deliberately ignores it. He appears depressed and knocks back another drink. The barmaid points out that this is the ninth call he’s missed and according to the screen on the phone, they’re all from work. She jokes about how much he must enjoy his work, but she’s unaware that her jealous boyfriend is watching from across the bar and is becoming increasingly angry. Owen dismisses the barmaid’s attention and tells her he wants to be left alone and when she tells him he should have stayed at home, he says the bigger the crowd is, the lonelier he feels. The boyfriend, Tommy, eventually comes over and shouts at the barmaid for chatting up the punters, but she argues it’s part of her job. Tommy accuses her of flashing her tits at every passing dickhead. Owen tells him not to speak to her like that, and an angry argument soon ensues. Tommy grabs Owen and tries to start a fight with him, but he’s no match for Owen’s experience or his bad mood. Owen holds Tommy in an armlock and advises him not to pick fights with strangers and tells the barmaid she should upgrade her boyfriend. He throws the man to the floor and takes another drink, and when his phone starts ringing again he switches it off.

Gwen tells Tosh that Owen still isn’t answering his phone and she says he’s been acting even more erratically than normal since his ‘thing’ with Diane. Tosh realises she’s said too much but it’s too late and Gwen presses her for more information. Eventually she’s forced to tell Gwen that Owen and Diane had a relationship before she left…

Jack goes down to the cell area and joins Ianto, who’s studying their Weevil prisoner. The creature is crouched down on the ground and appears to be wailing, as if in pain. Ianto says it started about ten minutes ago. Jack thinks the Weevil is weeping and Owen had already concluded they have a low level of telepathic ability and can share emotions across distances. They assume this one must be feeling the pain of the one they saw in the car park earlier, which means someone is not only kidnapping Weevils, they’re also torturing them! Jack tries to communicate with the creature and wonders what it can feel…

Tosh has successfully tracked the white van’s route from the car park to the Cardiff Bay docks. They watch the CCTV footage as the van screeches to a halt outside a warehouse, then the masked men carry the struggling Weevil inside. Then for some unknown reason, the CCTV cameras break down and the image is lost. It was obviously deliberate, so these men clearly don’t want to be watched, which only makes Jack even more curious.

The next morning, Jack and Tosh drive to the building seen on the CCTV footage. They start to explore, unaware that they themselves are now being monitored on camera. The area has been abandoned, but Jack thinks that if they left in a hurry they may have left something incriminating behind. They search inside the empty warehouse and Jack recalls that during the Second World War, they were used to store the bodies of dead GIs. Tosh is curious about this statement and Jack claims that he knows too much history. They draw their weapons and move further into the building. Suddenly Jack spots what looks like a dead human body and they approach cautiously. Jack calls out and says he’s looking for the people who were here last night. As they get nearer, they realise the man is indeed dead and is lying in a pool of blood and his body is covered in Weevil bites. Just then, the man’s mobile phone rings and Jack answers it. On the other end is an anonymous male voice which warns them to stay out of things that don’t concern them. Jack accuses the man of being a coward and a murderer and says they’re going to hunt him down, take back the creature that he kidnapped and then make sure he’s punished for what happened here. The man hangs up and Jack uses the phone to call Ianto back at the base and asks him to trace every call made and received on that number in the last 24 hours.

Owen has eventually been contacted and has agreed to come back to perform an autopsy on the dead man. He’s been identified as Dan Hodges, born in 1979. He was a salesman for a web publishing software company and his wallet contains a photo of his young wife and a child. Owen confirms that he was definitely killed by a Weevil, but he also suffered from other major injuries before his throat was punctured. Weevils always go for the straight kill, so they wouldn’t have been responsible for the bruises or the black eye. It’s possible he was tortured first and Owen is convinced the injuries were inflicted by another human. Ianto has checked the phone, but the last incoming number was blocked and the entire memory has been erased. Whoever they’re dealing with has worked very fast. Jack theorises that people are using the Weevils to carry out the perfect murder - no fingerprints, no traceable DNA, just a quick, guaranteed death with nothing to connect it to anyone. Gwen realises someone has to break the news to the man’s wife, and everyone turns to look at her…

Later, Gwen leaves the home of Dan Hodge’s widow and returns to the car where Owen is waiting for her. She hates the fact that she can’t get away from the worst part of being a police officer, but Owen remains completely silent and offers her no support. They start to bicker, and then Gwen asks him about Diane. He admits that he didn’t want Diane to go, but she did go and there’s nothing more he wants to say. Gwen demands to know why they’re still having a relationship, but Owen is clearly depressed and tells her he was getting bored of her anyway, so he calls everything off. She shouts abuse at him and when he gets out the car, she drives off.

Owen returns to the Hub and ignores questions about why he walked instead of coming back with Gwen. In his absence, Tosh has had an idea - if the kidnappers took the Weevil straight to the warehouse, they must have known it would be empty, so either they own it or they’ve had previous contact with the estate agent. Jack asks Owen to go undercover and find out what’s going on and Tosh starts preparing a cover story for him. It has to be Owen because Jack, Gwen and Tosh have all been spotted already by the kidnappers, either in the car park or at the warehouse. Owen doesn’t mind - he could do with being someone else for a while…

Owen arrives at the Lynch Frost commercial estate agent company that owns the warehouse. He’s smartly dressed and carrying a suitcase, which fits nicely into the upwardly-mobile image that his fake company represents. He meets the manager, Mark Lynch, and tells him he wants to relocate his business to Cardiff. He claims he runs a jellied-eels export company and says it’s a huge growth market and he’s currently having a nightmare trying to keep up with demand. He says he has no family and he’s looking for a nice big warehouse out by the docks. Lynch tells him he has a couple that should be perfect and while he goes to collect the paperwork, Owen attaches an alien device to a nearby computer screens. Back at the Hub, Tosh instantly gains access to everything on the company’s hard-drive, including all their encrypted files. Tosh tries to establish a routing protocol to give them permanent access so they can view everything he does on the computer from now on. It works and Owen removes the alien device just seconds before Lynch returns with the necessary documents. Owen flicks through the examples and dismisses them all as shitholes. He tells Lynch that he spotted their signs outside a warehouse by the docks, but the manager says they’ve already accepted an offer on that location. Tosh communicates secretly with Owen and tells him that’s a lie - the property only went on the market last week and is still available. Lynch tries to tempt Owen with a unit on an industrial estate and when they fails, he suggests they meet up again at the end of the day to discuss other possibilities over a drink.

Lynch is clearly suspicious of Owen and as soon as he’s left, he goes to the internet and begins searching on the internet for the fictitious jellied-eels company. This was entirely predicted by the Torchwood group and at every stage of the search they’ve created genuine-looking information for Lynch to read. He enters the company website and then goes to find out what other people have said about the business. Then he clicks on the company video to see Owen proudly talk about how successful his export company is. Finally, he calls the telephone number given on the website - and goes straight through to Tosh, who answers as if she was the company receptionist. Lynch claims he rang the wrong number and hangs up, but Tosh knows he’s been convinced. Ianto arrives and tells Jack he’s tracked down another set of suspicious looking injuries at the hospital, so the two of them go to investigate. Gwen wants to come with them, but Jack tells her to go home instead.

Gwen does return home and finds Rhys preparing to go out for the night. She recognises that he’s wearing his “pulling top”, the name he gave his favourite shirt after Gwen told him he looked sexy in it. He tells her he’s going on an all-day ‘staying single stag party’ for a friend who thinks he’s missing out on a piss-up by not getting married. Rhys pointedly tells Gwen he’s planning to have a few beers and see what happens, maybe they’ll even go to a strip club… She tries to tell him she’s staying in tonight, but he simply replies that he’s not and then walks out.

Jack and Ianto visit Will Harris, the patient with suspicious injuries in hospital, and draw the curtains to give them some privacy. Jack checks the hospital records and discovers he had his heart nearly torn from his rib-cage and had to undergo a ten-hour operation to repair the chest wounds. Will is reluctant to talk to them and says he’s already given a statement to the police, but Jack already knows what did this to him and accurately describes a Weevil. Will claims he was mugged by three men with knives, but Ianto points out that the doctors described the wounds as bite marks. Jack thinks the easiest way to get him to talk is to emphasise the consequences if he refuses to help - and that is the creature will attack again, somebody will die and it’ll be on Will’s conscience forever. Will says they’ll kill him if he talks and when Jack asks who, he says ‘everyone‘.

Jack, Tosh and Ianto return to the cell area underneath the Hub. They only have one option now - it’s time to take their prisoner out for a trip. They release Janet the Weevil (so named because Barbara never seemed right) and drive it to the middle of Cardiff. They place a tracker in its boiler suit so that when it’s captured, they’ll know exactly where it’s being taken. Tosh and Ianto are worried that the Weevil could kill any number of people before then, but Jack plans to release it in the multi-storey car park. It’s the same place where the kidnappers took the other one and it should be deserted at this time of night. The SUV comes to a stop and the Weevil jumps out and races into the distance. The tracker is working, so they wait a moment and then give chase. Unfortunately they soon lose it when it runs into a pedestrian-only area. The SUV can’t get access, so Jack and Tosh decide to chase the Weevil on foot while Ianto drives ahead to meet up with them later.

Owen and Mark Lynch have met up for a drink in the same bar that Owen visited earlier. Unfortunately the abusive boyfriend Tommy turns up with two of his mates and they approach Owen threateningly. Lynch challenges them, but they’re only interested in Owen. Owen stands up and confronts the men and a violent fight immediately breaks out. The three thugs have no chance against the expert fighting skills of both Owen and Lynch, and they’re quickly overcome. Lynch then watches with a mixture of surprise and admiration as the obsessed Owen continues to kick the boyfriend viciously, even when he’s lying unconscious on the floor.

Jack and Tosh race through the back streets and then take cover as the white van screeches to a halt not far away. Some masked men emerge and stun the Weevil into submission, then give it several kicks for good measure, load it into the back of the van and drive off. Tosh is angry with Jack for putting the Weevil through that punishment, pointing out that they would never allow that to happen to a human, but Jack reminds her that they needed to find a way to follow it. Ianto arrives in the SUV and they prepare to go after the white van.

Lynch takes Owen back to his house and tells him to make himself at home. Owen thinks he’s in the wrong business - the house is enormous and filled with the latest technology. The walls are covered with posters of boxers and there’s a punch-bag in the middle of the lounge. As Lynch changes into a new shirt, Owen notices he has terrible scars on his back, like claw marks. Lynch asks him what he uses as an outlet for his anger, and when Owen denies that he’s angry, Lynch points out that he’s not even living in Cardiff yet, and he’s already got people coming after him. Lynch isn’t criticising him - he’s says he’s not the only pissed off bloke out there. It’s what the world does to them. He says people like them work themselves stupid to get a house and a car, they get their own workforce whose role in life is to look after their every whim…but what does it bring? He says success isn’t worth having in itself and he doesn’t want to be defined by his possessions. He asks Owen what the point of life is and tells him there’s so much more if only he knows where to look. He tells him there’s something out there, in the darkness, and it’s coming…

By the time Rhys gets back home, Gwen has prepared two drinks for them. He tells her he only stayed for two pints and the others went on without him. They sit down together, both aware that they need to have a serious conversation, but neither of them knowing where to start. Eventually, Gwen tells him that she’s been having sex with someone else from work. She starts to give him more details, but he tells her to shut up. He doesn’t believe what she’s saying, but she insists it’s true. She’s telling him this because she’s ashamed and she’s angry and she needs him to forgive her. She also admits that she’s drugged him with an amnesia pill and he’ll wake up tomorrow having forgotten everything. He’s suddenly overcome by the drug and slumps back down on the settee. He accuses her of being a selfish pregnant dog and she agrees with him, she just wanted a chance to get everything out in the open. She begs him to forgive her, but it’s too late and he slips into unconsciousness.

At Lynch’s house, Owen goes upstairs on the pretext of looking for the toilet. He searches around and looks into several rooms, until he comes across a door that‘s padlocked. Making sure he’s not being watched, Owen opens the padlock and goes inside the room. It’s dark inside and filled with a mixture of boxing and martial arts equipment. Owen draws his gun and explores further…and encounters a Weevil chained up. Suddenly Lynch appears and Owen hides his gun and makes an excuse about never being able to resist a padlock. Owen asks him what the creature is and he admits he has no idea. They found it on the street and it took five of them to bring it in. It could be a scientific experiment gone wrong, a nuclear victim or even an alien. Personally Lynch thinks it’s what the human race will become in a thousand years when all that’s left is their rage. All he knows for certain is that it’s vicious - which he demonstrates by going up to the chained creature and punching it violently as if it was a punch-bag. After several seconds, Owen orders Lynch to stop, arguing that the creature isn’t exactly putting up a fight! Lynch realises Owen is connected to the people driving the SUV and he congratulates him on the fake website, although jellied-eels probably wasn’t the best idea. He tells Owen that he’s messed up his plans, but Owen counters this by asking about Dan Hodges’ wife and kid. Lynch argues that he’s not responsible for people’s life choices. He’s curious to know why Owen’s people haven’t gone to the police and Owen tells him the police wouldn’t be able to cope. He shows Lynch his gun, but Lynch tells him he’s not going to find the answers he wants through a weapon. Owen throws the gun away and Lynch admires him for this. Owen thinks Lynch arranged for Dan Hodges’ murder using the Weevil as a weapon, and Lynch realises they still don’t have a clue what’s really going on. He says Dan wasn’t murdered - in fact, he was one of Lynch’s group. He promises to show Owen everything…

Jack, Ianto and Tosh drive through Cardiff following the trace from the Weevil’s tracker, but they soon realise it’s stationary. Eventually the SUV pulls up at the location indicated on their scanner. After a quick look around, they find the tracker, still attached to a ripped section of the Weevil’s boiler suit and hanging from a nearby fence. They still have no clue who the people are, where they are, or what they’re doing!

Lynch takes Owen for a drive and they stop at the end of an empty street. The white van is parked nearby, but there’s no sign of any other activity. Eventually a man appears and walks towards a security door at a large building nearby, where he’s let in by two bouncers. Then two more men arrive and do the same thing. After that, some more people…and before long, the road is filled with young men all heading towards the same building. Lynch tells Owen he’ll find all the answers he wants inside, so they get out and head towards the others…

Gwen returns to the Hub with some pizzas, but finds there’s no-one there. She settles down and tries to eat one of the pizzas, but breaks down in tears. Then a mobile phone rings again and she looks around and sees the dead body of Dan Hodges, still covered in a shroud on the autopsy table. The phone rings again and she finds Dan’s phone in a plastic envelope by the side of the table. She sees he’s received a text message containing just a postcode - CF10 6BY. She rushes over to Tosh’s computer and enters the postcode and it comes up with an address owned by the Lynch Frost company. She contacts Jack who’s still en route back to the Hub with the others in the SUV, and she tells them what she’s discovered. They realise people are being lured by text message to an address which Mark Lynch knows will be empty. The question is - what happens when they get there? Jack tells Gwen he’ll pick her up on the way, then they’ll head for the address…

Lynch takes Owen inside the building, which is now heaving with dozens of young men, many of whom are engaged in fist-fights and being cheered on by others who are watching. Lynch explains to Owen that they’re just “warming up” and they’re ordinary blokes trying to find meaning in a world that doesn’t have any. Lynch believes this generation are the dispossessed - all the certainties their fathers had about the world have gone. They have no faith in religion, society or in life. All they can do is reduce themselves to the basics. He leads Owen further into the building and they pass room after room filled with people recovering from the injuries they’ve received during their “warming up” sessions. He takes Owen into the main area - an arena overlooking a large cage in which a young man is currently fighting for his life against a Weevil. At the side of the cage is a display screen indicating how long he’s been inside and all around the arena, other men are drinking and cheering, filled with blood lust and urging the fight on. At one stage the man in the cage falls and the Weevil advances, only to be warned off by a guard outside with a cattle prod. The man leaps to his feet and reaches the safety of an inner cage, where he waits to be released. Lynch explains that everyone who enters the cage has to pay £1000 and whoever stays in there the longest at the end of the night gets to keep all the money. These men are paying to put their lives at risk - it’s the ultimate extreme sport. They have too much disposable income and not enough meaning in their lives. Owen asks about Dan Hodges and Lynch tells him he refused to come out of the cage. He just stood in the middle and let the creature maul him to death. Lynch thinks Hodges didn’t want to live enough and just surrendered himself.

Owen tells Lynch this has to stop and goes to leave, so Lynch chases after him. He catches up with him and tells Owen that it’s clear he’s hiding from something. He pulls a gun on Owen and orders him to get into the cage. Owen refuses under these circumstances, but says he’ll go into the cage if Lynch lowers the gun. At first Lynch stands firm, but Owen approaches him without fear and eventually Lynch drops his arm. Then Owen removes his jacket and heads straight into the arena. Lynch tells him Dan Hodges holds the current record and advises him to get up close to the creature and look into its eyes - it’s like looking into the dark recesses of your own soul. The door to the cage is opened and Owen enters…

The door is locked behind him and Owen starts to circle round the cage, facing the Weevil. For a moment, he smiles…then he closes his eyes and whispers to the creature to get on with it. Suddenly the main door bursts open and Jack and the others burst in. Jack fires his gun into the air - and while everyone is distracted, the Weevil takes its chance and attacks Owen! As he falls to the floor with the creature on top of him, Gwen orders the guard to open the cage door. The Weevil starts to bite into Owen who screams in agony, so Jack has no choice but to shoot the creature in the arm. The wounded animal backs away, giving Gwen time to get to Owen, who screams at her to leave him alone. Jack helps her carry Owen out and Lynch calls for a stretcher. Meanwhile, Ianto and Tosh have arrived and are holding the others at bay with their weapons drawn. Jack accuses Lynch of trying to kill Owen, but Lynch tells him Owen did it to himself and that he had no fear. Jack stands before the baying crowd and tells them everything is over now and they should go back to their lives and leave the creatures alone. While his back is turned, Lynch voluntarily steps into the cage and locks the door behind him. He faces the Weevil and tells Jack everything is over. The Weevil won’t attack while Jack is pointing his gun at it, so he lowers it and allows the creature to lunge towards Lynch. The room is filled with his screams and Jack turns to leave.

Owen is alone in hospital with his wounds bandaged up. Jack arrives and throws some grapes at him, but Owen says he shouldn’t have…because he hates grapes! The doctors have told Jack that Owen’s ready to go home, but Owen doesn’t seem very keen. He tells Jack that he didn’t want to be saved. Jack refuses to apologise but Owen says that for the few seconds he was in the cage he felt totally at peace. He questions whether Jack always knows what’s best, but Jack faces him off and tells him he wants him back at work tomorrow.