A happy crowd gathers to watch a parade, blissfully unaware of the presence of death; for in a nearby building, an assassin is watching, waiting for his target to arrive. Long before the parade comes into sight, however, a strange little man with a Scottish accent shows up in the room -- but he has no intention of stopping the assassin. Rather, he’s here to tell the man a story. For some reason, the assassin listens to the little man as he begins his tale...

The story begins on the outskirts of a town called Perfugium, in an old house where the kindly Dr. John Smith is waiting for his two best friends to arrive. Inspector Victor Schaeffer and his wife, Jacqueline, have braved the gathering storm to visit their friend for his birthday celebrations, or, rather, the day they celebrate as such. John’s young maid, Jade, greets the visitors and shows them to the study, where John is waiting for them. He greets them warmly and apologises to Jacqueline for failing to attend to his duties at the sanatorium; he has been somewhat under the weather for a few days, but claims he is feeling better now.

John pours drinks for his guests, but Victor firmly insists that his wife take only a small glass. The friends’ small talk touches on the grand house, which John inherited from a former patient named Wolstonecroft, along with his maid -- and, according to Jacqueline, a curse. This colony was founded by Jacqueline’s family, the Uttersons, all staunch and upright citizens -- all but the black sheep of the family, Sir Joseph Utterson, who lived a life of debauchery within this very house. One day, he mistook an ordinary girl for a lady of the night, plied her with drink and brought her to his home; she died during their subsequent “revels”, and her grieving father slaughtered Sir Joseph and his servants and placed a terrible curse on the house. So the story goes, although Victor dismisses it as superstitious rubbish.

John leaves to check on the progress of dinner, and while he’s gone, Victor chastises his wife for treating John as if he’s incapable of caring for himself. He admits, however, that he’s out of sorts because of his recent investigation; a serial killer is stalking Perfugium, and the most recent death has shaken Victor badly. He tries not to show it, however, for John’s sake. John returns and shows his friends to the dining room, and on the way, his friends tell him about their recent night at the theatre. They witnessed a disappointing opera, a foolish tale of murder and mayhem. Jacqueline was disappointed by the poor production values, and Victor was disappointed by the poor characterisation, as no motive was given for the murderer’s actions. John admits that he’s begun to wonder whether evil must necessarily be motivated -- but he’s interrupted by Jade’s cat, which yowls at him and bolts, breaking up the conversation.

As John and his friends dine, Jacqueline notices that she doesn’t have a knife, and leaves to fetch one. John takes the opportunity to ask Victor about the tension he’s noted between them, and Victor confesses that there’s been another killing; an innocent girl’s throat was slit and her heart cut out of her chest. Victor had to tell the girl’s family, and he feels responsible for their grief and desolation.

Terrible sounds like evil, whispering laughter seem to pursue Jacqueline through the house; however, they stop when she enters the scullery. Shaken by what she’s heard, she is thus harsh when she confronts Jade, who seems surprised to learn that the table setting is incomplete. Before returning to table, Jacqueline pauses to tell Jade a little about her new master. Ten years ago to the day, Dr. John Smith was found walking the streets of Perfugium with no memory of his past. His hideously scarred, corpse-like face suggests that he was involved in some terrible accident, but apart from that nothing is known of the man he once was. Jacqueline is aware that, despite his appearance, young women may be attracted to John because he is both genuinely good and a man of mystery -- but Jacqueline makes it very clear that these attentions are unwanted. Jacqueline takes her leave, and as Jade prepares dessert and later does the washing-up, she finds herself singing a strange nursery rhyme about a being named Zagreus.

Back in the dining room, the friends discuss Jacqueline’s work at the town hostel. Victor is unhappy that his wife consorts with such lowlifes, as he believes that the homeless and those without proper families will naturally descend into crime. Jacqueline admits that she may be motivated from guilt about her own privileged upbringing. Victor convinces John that even he tends to judge people, albeit subconsciously; for example, they are all more horrified by the murder of the innocent girl than by the murders of the prostitutes who preceded her. The conversation also touches on John’s amnesia; despite all his effort and the books he’s read on the subject, he is no closer to finding out who he used to be.

Soon dinner and dessert have gone and Victor is quite drunk. Despite Jacqueline’s efforts to dissuade him, Victor rises to make a toast to his old friend, but as he does so, his mood turns ugly. Claiming to have blood on his hands, Victor drunkenly lashes out at John, demanding to know what evil secrets he’s hiding behind his amnesia. Victor then realises what he’s said, and, horrified, he begs John for forgiveness. There is an awkward moment as John deals with the revelation that his old friend apparently harbours hidden fears and resentments towards him, but he nevertheless manages to make light of the situation and suggests that this is just Victor’s nature. As an Adjudicator, it is his job to categorise people either as criminals or law-abiding citizens, and John’s amnesia makes it difficult for Victor to judge him. Despite the awkwardness, John and his friends manage to relax again, and Jacqueline decides to give John his “birthday” present.

Jacqueline screams and recoils, shattering the glass and cutting herself; she’s just seen a man at the window, his face contorted in agony. She tries to stop John and Victor from going out to find the injured stranger, convinced somehow that the man intended to do them harm. John and Victor venture out into the storm nevertheless to find the man, who appears to have been struck by lightning. Despite the stranger’s injuries, John finds his face oddly familiar. He and Victor take the man into the study, where he revives -- but when John asks his name, the man says only “Death”, and then begins to scream.

The assassin is not impressed with the story so far, and questions why he should listen to a tale populated by such unlikeable characters. Victor claims to be John’s friend, but secretly fears and hates him; Jacqueline claims to feel guilty about her privileged upbringing, yet still upbraids and patronises John’s maid; John seems sane, but he has no memory of his past; and the man claiming to be Death is obviously mad. Nevertheless, the storyteller claims that this is a true story, and assures the assassin that it’s about to get better.

Victor and Jacqueline return to the dining room while John tends to the burned man. Eventually the man recovers and revives, and John offers him water and kindness -- but can’t refrain from asking the obvious question. Does the stranger know him? The stranger is taken aback by the question, and seems horrified to learn that he’s arrived in Perfugium; nevertheless, he claims that he’s never met John before. John is disappointed, but warns the stranger that a serial killer is stalking the colony. The stranger asks to know more, claiming to be concerned for the safety of a friend, and John explains that 11 prostitutes -- and one ordinary teenage girl -- have been murdered, their throats slit and their hearts cut out, and their bodies draped in a green blanket, a symbol of death and a return to nature.

The stranger is intrigued, and compliments John on his extensive library, containing works of fiction, professional and amateur texts on the subjects of evil and abnormal psychology. John has been trying to profile the serial killer, but recently he’s begun to question whether killers must necessarily always have a motive. As he speaks, he realises that he’s treating the stranger as an old friend even though he doesn’t know the man’s name. The man admits that he too is a doctor, and although it seems as though he is going to give the name of John Smith as well, he corrects himself and gives the name of Dr. Vaughn Sutton.

John lets the matter slide and continues his musing on the nature of evil. The Doctor claims that he’s met people who believed that evil was a physical force that corrodes the soul; he told them that evil was relative, but lately he’s come to wonder whether some people are just born evil. He once knew a man who committed terrible acts without ever seeming to have any real motive. He labelled this man a monster, but John suggests that perhaps he was trying to separate himself from the other man -- trying not to understand him, for fear that if he did, he would acknowledge that they were similar. The Doctor concedes the point, but still claims that the man he knew was truly evil... and he was known as the Master.

John seems to find this name familiar, but the Doctor changes the subject, claiming that it’s too painful for him to discuss. Again, John lets the matter slide and resumes their discussion of the philosophical nature of evil. Is there an objective reality to the Universe, or is it all relative? How does John know whether he and the Doctor think of the same colour when they think of “red”? Perhaps those who are considered evil by others merely see the Universe from a different perspective. But perhaps there is another sort of evil; perhaps there are those who are fated to kill, and who cannot escape their destiny -- as much as they may wish to...

John’s interest in the subject of evil dates back to his arrival in Perfugium as a man with no past, but he confesses that his thoughts have grown darker and more disturbing recently -- ever since he moved into this house, which some say is haunted. Somehow he finds himself able to confide his darkest secret to the Doctor; recently, while delivering a baby, he was suddenly possessed of the urge to dash the newborn’s brains out against the floor. Of course he did no such thing, but where did this sudden urge come from? Was he an evil man in his previous life?

John has mentioned the curse in passing, and he now admits that this is the real reason he invited his friends here tonight; not just to celebrate his birthday, but to see if they felt the same sense of oppression as he does in this allegedly haunted house. He’s been disturbed by the results, especially as Victor has been so terribly affected by the recent murders. This raises an uncomfortable question, but John has already asked it of himself and is sure that he can’t be the killer. Some days ago, John surprised an intruder in his home, but despite his anger -- and the opportunity -- he found himself unable to lift a fireplace poker to kill the intruder. He’s convinced that he doesn’t have it within himself to commit murder, but this suggests that his disturbing fantasies and Victor’s behaviour have been influenced by some external force. Even as John speaks, a book falls from its place on the library shelves.

The assassin is starting to become interested in this story now. Is John Smith really the Master, as the stranger implied, or was that whole story a lie? And if it wasn’t the spirit of the Master which possessed John, then what other force is at work in the house? The storyteller resumes his story, picking up with Victor and Jacqueline in the dining room...

Despite Victor’s assurances, Jacqueline remains convinced that the newcomer means to do them harm and that the innocent John is unaware of the danger he’s in. Jade begins to offer her opinion, but Jacqueline unexpectedly slaps her for her presumption and drives her from the room in tears. Victor is appalled, as is Jacqueline when she realises what she’s done. It seems that she too is being affected by the dark forces unleashed within this house. John returns to advise his friends that the stranger will be spending the night here, but as he speaks, they hear Jade scream, and rush from the room to find that her cat has been brutally slain. John manages to calm down his maid and asks Jacqueline to take her to the scullery. As they go, John pulls down the nearest curtain and covers the cat’s body, but then realises that Victor is too shaken to move. The cat’s throat was slit and its heart removed, and now its body has been covered by a green cloth, just like the serial killer’s victims -- so like them that Victor regards it as a personal taunt.

“Dr. Sutton” then bursts out of the study in a panic, claiming to have been attacked. As he, Victor and John take stock of the damage, the Doctor quotes from Dr Jekyll and Mr Hyde. Victor accuses the Doctor of vandalising the laboratory himself, but John points out that one man could not possibly have caused so much damage in so short a time. Things are worse than he had imagined, and when Jacqueline arrives with Jade, John finally admits why he really invited his friends to the house. Victor is enraged with John for deliberately placing Jacqueline in danger, and is even more furious when Jacqueline again takes John’s side. Nevertheless, though it’s clear that they’re in danger here, going out into the storm would be just as dangerous; the occupants of the house are stuck here.

Jacqueline tries to calm everyone down and discuss the situation rationally. There seems to be a connection between the recent murders and the legend of Sir Joseph Utterson, which is odd, since nobody really believes the story. In fact, Jacqueline only ever heard the story of the curse from Wolstonecroft, the man who owned the house before John Smith -- the same man who decorated it in the colours of death. John questions the Doctor, certain that his arrival is no coincidence and that he is himself the “missing friend” whom the Doctor is searching for. But if this is the case, why does the Doctor deny that this is the case?

Victor demands to know exactly who the Doctor is and why he is here, but the Doctor in turn points out that Victor has been behaving oddly tonight. Someone in this house must have killed the cat, but whom? Jacqueline attempts to restore sanity to the proceedings by suggesting that they work together to clean up the study. The Doctor and Victor rearrange the furniture while John and Jacqueline re-shelve the scattered books. However, John remains convinced that the Doctor knows John from his past life... and if this is the case, why does the Doctor seem so unwilling to admit it? John admits that he’s felt something evil struggling inside of him for the past several weeks, and fears that these are memories of his past life. As he struggles to understand what’s happening, he happens to find the dinner knife which Jacqueline claimed was missing from the table earlier...

The Doctor tries to convince Victor to take his wife and leave while he still can; there are terrible forces at work within the house, and although the Doctor has deduced the reason for the prostitutes’ murders, he claims that they are relatively unimportant when compared to what else has been unleashed. Before Victor can demand an explanation, John holds the dinner knife to Jacqueline’s throat, threatening to kill her unless the Doctor admits the truth. The Doctor is forced to reveal that he does know who John once was, but he realises what John is doing and refuses to tell him any more. Victor, fearing for Jacqueline’s life, attacks the Doctor and tries forcing him to admit the truth, and John and Jacqueline are forced to drop the charade and admit that they were trying to trick the Doctor into revealing the truth. Stunned, Victor lashes out at his wife for putting him through such terror for John’s sake when he’s devoted his life to protecting her from harm. As Victor sobs in despair, the Doctor realises that he’s been manipulated into a position where he has no choice but to reveal the truth to John.

The Doctor confesses all to John and his friends. Long ago, on a distant planet, there were two young boys, best friends who were tormented by a bully named Torvic. Torvic was not truly evil; like the boys, he just wanted to break the rules and take command of his own life. But one day he went too far, pushing one boy’s head under the water and holding it there -- until the boy’s friend grabbed a rock and struck Torvic in the head, killing him instantly. The boys burned Torvic’s body and vowed never to speak of this again, but from that day on, the killer became more and more distant and angry, as the guilt and rage ate away at him from the inside. Eventually both boys left their homeworld, but while the one known as the Doctor explored the Universe, seeking out wonders, making new friends and righting wrongs, the killer became known as the Master, and he spread horror and death wherever he went, sometimes destroying whole worlds such as Traken and Duchamp 331. He had no motive for his actions; he had become, quite simply, evil for its own sake.

Now the assassin is really into the story, and he eagerly awaits and anticipates the next twist of the plot. The storyteller continues...

A stunned silence follows Jade’s revelation, and she takes the opportunity to mock her foolish victims -- particularly the Doctor, who realised far too late that her name, Jade, means green, the colour of death on Perfugium. When Jacqueline tries to speak up, Jade closes her mouth and her throat with but a gesture, but releases her, amused, when the Doctor begs for her life. Jade then reveals her victims’ remaining secrets; the Doctor came to this house to kill John, Jacqueline is in love with John and not her husband, and it’s Victor who has been murdering prostitutes in the streets of Perfugium. Victor flees, screaming, at least as much from the revelation that his wife loves another, and Death laughs as all the lights in the house go out.

In the darkness, Jacqueline calls out for John, and when he responds, she admits that she has always loved him; she only married Victor because her mother insisted that she marry an upright pillar of the community rather than a deformed doctor with no memory of his past. She still loves John, but John announces that he’s accepted tonight’s revelations. He is the Master, he is evil, and he is fated to cause death and destruction wherever he goes. He coldly informs Jacqueline that he’s never loved her in return, and mocks her foolish attempts to assuage her guilt at her privileged upbringing by running a hostel. He advises her to leave or to stay; whichever she decides to do, he does not care.

Jacqueline retreats in tears, leaving John alone in the dark -- but for the Doctor, who has been standing silently in the shadows, listening to everything. He understands that John truly does love Jacqueline, and that he was trying to save her life by driving her from him before Death returned. The Doctor admits that the Master has always been Death’s servant, but ten years ago, Death came to the Doctor in a dream, and they made a deal. Death would relinquish her hold over the Master for ten years, giving him the chance to live the life she took from him; in return, the Doctor had to kill him when those ten years were up. Death set in motion the events of this terrible night to manipulate the Doctor into keeping his promise. John, now understanding that everything hinges on him, asks the Doctor to fulfil his bargain and save the lives of untold future millions by ending John’s life now, with the knife with which John pretended to threaten Jacqueline earlier.

Jacqueline is lost in the dark, and evil whispers are trying to lead her astray. Jade’s voice taunts her as she stumbles over the body of the slaughtered cat. She eventually finds her way to the scullery, where Victor is sitting alone, lost in his thoughts. He admits that he killed the prostitutes, but insists that this was his duty as an Adjudicator and a loving husband. He could see Jacqueline losing her innocence as she tried to help the unfortunates at her hostel, and he killed them to save her. He regrets only his most recent victim, an innocent girl whom he killed by mistake; the others, he claims, were beyond saving. Jacqueline refuses to believe that anyone is beyond saving -- but doesn’t that mean that Victor himself can be saved?

The Doctor can’t bring himself to kill John, even when John begs him to do it for Jacqueline’s sake. In fact, this gives the Doctor pause for thought. Death gained its hold over the young Master when he killed Torvic, after which he felt fundamentally disconnected from the rest of humanity. The Doctor’s deal enabled John to live in a community for ten years and feel a sense of belonging -- but love never entered the equation. If John and Jacqueline truly love each other, perhaps John will be able to change himself and break free of Death forever. The Doctor and John set off to find Jacqueline, realising that if Death gets to her first, there will be no hope left, and John Smith will be doomed to become the Master once more.

Jacqueline tries to soothe Victor, but to no avail; the voice in his head, Jade’s voice, is telling him that he is the only one who can put right what’s wrong with the world. He begs Jacqueline to admit that she loves him and not John, but Jacqueline cannot do so. When the Doctor and John arrive, Victor begs the Doctor to tell Jacqueline that John is evil and beyond redemption, and must be killed, just as Victor killed the prostitute who were corrupting his society and his wife. John, Jacqueline and the Doctor all try to convince Victor that he’s being used as a pawn by Death, and that he must let Jacqueline go of his own free will. Death has manipulated them all into this position, and only Victor himself can break her hold over him. But he can’t bring himself to do so; he loves Jacqueline, and now he knows that she will never love him in return. Before anyone can stop him, Victor kills Jacqueline.

As John wails in despair, Death stops Time in order to gloat. John is beyond her reach now, but the side of him that is the Master responds to her call, free at last. He is furious with the Doctor for trapping him within the persona of John Smith, and rejects the Doctor’s claim that he is evil; however, the Doctor insists that the Master’s desire for knowledge and power has led him to evil and caused the deaths of innocents. The Master scoffs, and dismisses the significance of thing that calls herself “Death”. The weak deserve to die, and friendship is a weakness, an excuse to give up without seeing things through to the end.

Jade dismisses the Master back to limbo, satisfied with the events of the evening; lives have been destroyed, innocents have been murdered, and it seems the Doctor has no choice now but to fulfil the bargain and kill the Master. However, the Doctor offers to make her another deal and let John Smith, not the Master, choose what to make of his future. Amused, Jade agrees to the deal, and allows time to start up once more. But before giving John the chance to make his decision, she reveals the final secret, the one which even the Doctor had forgotten. Torvic was killed, not by the boy who would become the Master, but by the boy who would become the Doctor. And when Death visited the guilt-stricken boy in the night and gave him a choice, he chose to give his friend to her instead. It was the innocent victim who suffered the guilt and self-loathing of the crime which his friend had committed, condemning him to a lifetime of loneliness, hatred and despair as the Master.

The Doctor is horrified, but senses within himself that what Death is telling him is true. But to his shock, John forgives him, understanding that the adult cannot be blamed for the foolish decisions made by a child who failed to comprehend what was being offered. Amused, Jade then offers John an opportunity to save Jacqueline’s life by killing Victor before he can kill his wife. John understands the implications; if he takes a life, he will become Death’s servant once more, but if he does not, then the woman he loves will die. Jade gives John a moment to discuss his decision with the Doctor, who is now wracked with guilt over what he did to his childhood friend. John forgives him, and makes his choice -- but Jade casts the Doctor away, punishing him for breaking their bargain by expelling him from Perfugium before he can even bid John farewell, let alone learn what he will decide to do.

The story thus ends where it began, with Victor and Jacqueline arriving at their old friend’s house to celebrate his birthday, only to find him waiting with a knife. But as the events of that terrible night have not happened, Jacqueline does not understand why John is behaving this way, and she is horrified when he threatens to kill her husband. John is torn with indecision; if he kills Victor, Jacqueline will live, but she will not understand why he has done this and he will be doomed to become the Master once more, servant of Death. What will he do?