The largest shopping centre in the galaxy, the Gigamarket on the planet Baladroon, is playing host to two very distinguished visitors today. Joggon, the head of the Vorax Corporation, is one of the Gigamarket’s most important investors, but Keelor, one of the Gigamarket executives, leaves him waiting in the VIP suite while he attends the other important visitor, Professor Bernice Summerfield. Benny is supposedly here to excavate the car park, where they’ve found three latrines from the dark ages of Baladroon -- but in fact, this is a minor dig, and she really intends to leave the job to her archaeobots while she nips into the Gigamarket’s shoe canyon with a credit chip she “borrowed” from Adrian Wall. Oddly, her porter Joseph is beginning to behave erratically, although he insists that his systems are functioning within normal parameters.

Keelor is a bit too enthusiastic of a fan, as Benny learns when he stops off on the way to the shoe canyon to show Benny the display he’s set up in the book department for Down Among the Dead Men. Benny is taken aback to see herself standing 30 metres high, tanned, fit, and wearing a Spandex bikini. She’s even more surprised to find that apparently she can’t afford her own book; Adrian has found out what she’s done and has reset his own chip’s spending limit to “lukewarm”. Benny will be lucky if she can even afford one pair of shoes. Nevertheless, she continues on to the shoe canyon, where the Gigamarket stocks every conceivable kind of footwear, including shoes made from real leather (donated posthumously by will and probate after the cow’s death). Before Benny can begin to browse properly, however, Joseph begins to go loopy again, and a time anomaly sweeps through the shop, transforming the shoes back into cows. Within seconds all is normal again, except for the dead cows in the aisles, and the fact that Joseph and Keelor’s watch both give the time as being sometime in the middle of last week.

Benny tries cleaning out Joseph’s systems to no avail; it appears that he’s being adversely affected by a genuine time anomaly. However, as another side-effect, Adrian’s credit chip has been reset, and Benny can get down to some serious shopping. Keelor must leave to attend an important marketing seminar, and he gives her a tracker so she can locate him if she needs any help later. As he departs, however, Joggon contacts him -- ostensibly to complain about the time anomaly, which is causing Gigamarket’s stock to plummet. Keelor promises to do all he can to correct matters, but Joggon privately seems entirely satisfied with events; in fact, he’s taking a great deal of pleasure out of it.

Benny becomes swept up in the experience of shopping, and at first fails to notice when alarms go off and her shopping assistant flees in panic. Eventually, she can no longer ignore the animal snarls and blood-curdling screams surrounding her. She is attacked by a monster which appears from nowhere, and she and Joseph flee, using the tracker to locate Keelor. He seems just as confused as they are, but at least he can identify the monsters; they are Borvali. A fifty-kilometre-high force wall encircles the entire planet, separating the human colonists from the Borvali Protectorate -- and somehow these Borvali appear to have penetrated it. More temporal anomalies ripple through the store, and Keelor receives an emergency message warning him, and all other executives, to evacuate the store immediately. Unfortunately, the Borvali are everywhere, and Keelor loses his bearings trying to find the way out. By the time they get to an exit, it’s too late -- a giant silver bulkhead appears from nowhere, a stasis shutter. All of the doors in the Gigamarket are sealed shut, and Benny is trapped inside.

Benny can’t make sense of what’s happening; if the Borvali have found a way to penetrate the force field, then why have they attacked a supermarket first? Keelor tries to lead her to the warehouse, hoping that there will be a way out through the loading bays, but on the way they are attacked by more Borvali -- and then rescued by human soldiers who appear from nowhere, wearing uniforms 100 years out of date. When the soldiers’ commanding officer removes his helmet, Keelor recognises his own grandfather, Lieutenant-Colonel Tarband Trance. Tarband and his outfit were supposedly killed in the last battle of the human-Borvali war, when the entire battlefield was vapourised -- an event so horrible that both sides agreed to the construction of the force wall, to separate their two species forever. Tarband has trouble believing that he and his men have travelled through Time, but he accepts that innocent civilians are at risk within the Gigamarket. He thus divides his forces; some of his men will help the surviving shoppers, while Tarband and the others engage the Borvali in battle.

Tarband insists that Benny and Keelor accompany him to explain the situation, much to Keelor’s distress, as he’d much rather be getting out of the Gigamarket. Unfortunately, when they do encounter some Borvali, Tarband’s men are hopelessly outnumbered, and all Benny, Keelor and Tarband can do is retreat, hide and wait for the enemy to move on. When they emerge from their hiding place, they find that a time anomaly has apparently transported them to an entirely different sector of the Gigamarket -- and before Keelor can stop her, Benny investigates the odd-looking “products” on display, and discovers that they’re human bodies. Keelor is forced to admit that, despite the prohibitions, Gigamarket executives have decided to open up trade negotiations with the Borvali, who were only interested in one thing. To prevent the species from mixing, the Gigamarket has been constructed in two separate temporal locations, but now it appears that the time engines are malfunctioning, causing the two zones to merge, and causing temporal anomalies as side-effects. Keelor must also admit why he’s so desperate to escape; a blanking bomb has been built into the time engines, to be activated in case of an emergency on this scale. The executives will be given time to evacuate, and the bomb will then destroy the entire Gigamarket, and all evidence of their criminal activity.

Tarband, disgusted, forces Keelor to lead them to central control, despite the risk of further Borvali attacks. They locate the time engine controls, but are unable to shut them down or access the blanking bomb from here; they’ll have to go directly to the engines themselves for that. Joggon then arrives, having used his own tracker to locate Keelor and complain. After forcing Tarband to hand over his own weapon, Joggon reveals that he bribed Keelor to sabotage the time engines in order to create bad publicity and depress the value of Gigamarket stock so he could buy it up in preparation for a hostile takeover. But being trapped amidst ravening Borvali while waiting for a bomb to vapourise him wasn’t part of the deal. Keelor has little choice but to lead them all to the time engine enclosure, but on the way, another time anomaly strikes and they find themselves surrounded by confused Borvali. Joggon returns Tarband’s gun so he can help defend their party, but Benny realises that these Borvali are disoriented women and children -- ordinary civilian shoppers from the Borvali sector of the Gigamarket. To her horror and disgust, Tarband opens fire on them anyway, regarding them all as the enemy.

More Borvali then arrive and attack -- presumably soldiers transported from the century-old battlefield just as Tarband was. In the confusion, Benny, Joseph and Tarband are separated from Keelor and Joggon. Benny is still disgusted with Tarband, but she needs his help to avoid the really dangerous Borvali while she tries to track down Keelor again; after what he’s caused trying to commit minor sabotage, she doesn’t trust him to defuse the bomb properly. On the way, they find a Borvali child who survived Tarband’s attack earlier, and despite Tarband’s protests, Benny treats its wounds. The Borvali may kill and eat human beings, but they’re just acting according to their nature; the real evil here lies in the exploitation of that nature by the Gigamarket executives, and the real enemies are Joggon and Keelor.

Benny and Tarband locate Keelor and Joggon in the time engine enclosure, only to learn that they’ve arrived too late. The bomb has already gone off -- but the explosion is replaying in a time loop of a few seconds. They still have a chance to defuse the bomb, if they act quickly -- but Joggon is unwilling to risk Keelor on the first attempt, and thus sends Benny in first, telling her to follow Keelor’s instructions. Each time she gets close to finishing her work, however, she runs out of time, and must retreat from the explosion and wait for the time loop to cycle back to the beginning again. To make matters worse, the Borvali attack again, and although they’re driven away by the blanking bomb’s explosion, Tarband has had enough. He attacks Keelor, who panics and shoots him -- but as a result of the time anomalies, Tarband is now too young to have given birth to Keelor’s father, and Keelor himself ceases to have ever existed -- thus he cannot have shot Tarband, who reappears, causing Keelor to reappear and shoot him again. This is the grandfather paradox in action.

The bomb is no longer exploding, since Keelor is cycling in and out of existence, and if he didn’t exist then he couldn’t have sabotaged the time engines in the first place. But the loop remains unstable, and as Benny and Joggon try to think of a way out, another Borvali attacks -- and this time, kills Keelor. Keelor dies in his timeline before he shoots Tarband -- but after he sabotages the time engines, which means that the bomb is still exploding. And only Keelor knew how to defuse it. Benny has had enough, and she begins bashing the time engines with her shoe, eventually smashing the controls to pieces and defusing the bomb. Joggon, satisfied, prepares to kill both Benny and Tarband, the only witnesses to his act of industrial sabotage; but before he can do so, the stasis shutters lift and his link to the outside world is re-established. The pleasure centres of Joggon’s brain have been index-linked to input from the Galactic stock market, and the Gigamarket stock has gone into freefall. Death by orgasm is one of the stranger things Benny has witnessed.