A man wakes up in his childhood home, suffering from a headache and vaguely aware that he's not actually 11 years old any more. The house is deserted, and as he examines it more closely, he comes to realise that everything is a little off-kilter, as if it's a model created by beings who have had a house described to them without ever having seen one themselves. He tries to escape through his bedroom window, only to find that the outside landscape is back-projected against an impermeable wall. Panic-stricken, he tries to cut through the wall with a knife, but cuts himself instead and passes out. When he wakes up later, he's still trapped in the house, but someone has bandaged his hand. For the next two days, he keeps trying to trick whatever put him here into revealing itself, and when all else fails, he cuts himself badly in the hope that he'll be removed from this place and taken to a proper medical facility. Only as he's passing out does it occur to him that if the creatures who put him here regard him as a lab rat, then they might decide to euthanise rather than repair him.
While asleep, the man dreams of a woman named Benny, who explains that her presence in the dreams is filling in gaps in his memory. He awakens to find himself being tended to by a bizarre alien with strange speech inflections, which is forced to leave the room to investigate the sound of alarms. A remarkably familiar voice then orders the man to pull himself together, and he looks up to see another version of himself standing in the room. The other version identifies the man as Jason, but not the real Jason; the man in the doorway is 2-Jason, and the man strapped to the table is 3-Jason. 2-Jason does nothing to help as 3-Jason tries to free himself from the medical equipment he's entangled in, and the alien returns before he can escape. However, a woman named Mira rushes into the room and tasers the alien before it can administer another dose of anaesthetic to 3-Jason. She's here to rescue Jason... but when she sees who's standing before her, she realises that she's got the wrong one.
The Jasons follow Mira out into the corridors of the facility, a laboratory complex in the Catan Nebula. While 3-Jason concentrates on walking, 2-Jason explains to Mira that the original Jason created short-lived clones of himself as part of a publishing scam, but the clones struck a deal with his publisher's rivals, ballsing up the original Jason's scheme in exchange for permanent bodies of their own. Only two of them existed when they made the deal, however, and a third clone was created over the course of the scam; thus, rather than fight amongst themselves, they put the money into escrow and waited until either they had enough for a third body or one of the clones had died. Unfortunately, their lifespans turned out to be even shorter than expected; the original Jason had decided not to pass on some of his more personal memories, and one of the clones shut down completely when his mind tried to access thoughts that weren't there any more. The surviving two clones came here to get permanent bodies made for themselves; 3-Jason was the first to arrive and be transferred into a permanent body, and 2-Jason was given a temporary memory patch so he could survive long enough for the technicians to grow a second body for him. While waiting, however, he came to realise that something shady was going on; instead of being given psychological help to integrate his mind fully into his new body, 3-Jason had been placed in an artificial environment in which his emotional progress had been deliberately halted at the mental age of 11.
Mira explains that her psionic implants had given her the impression that Jason was in danger; she thus rushed off to rescue him, but accidentally rescued the wrong ones. Or rather, she's still in the process of rescuing them, because the station has been attacked by the Church of the Righteously Ascended Pure; they have very firm beliefs about genetic engineering, alien hybrids, and what constitutes a "real" human being, and they tend to put their point across using flamethrowers. As Mira tries to work out a safe path back to her shuttle, 3-Jason realises that he's being distracted by thoughts about dogs for some reason, and that he still thinks of his childhood memories as more real than the events he's currently experiencing. If he gives in to the pull of his memories, he'll fall into a coma and be trapped in his horrible childhood for the rest of his life. He thus makes an effort to pull himself together -- and is nearly floored by the rush of traumatic memories as he recalls going after his abusive father with a knife, beating his girlfriend until she left him, and then stalking her to a women's shelter and beating her so badly that she miscarried their child. 3-Jason is unable to live with what he remembers doing, and 2-Jason practically has to carry him onwards as he begins to sink into suicidal despair.
Mira's shuttle is guarded by followers of the Church, but she attacks them and does enough damage to make the survivors run away very quickly. Mira and the Jasons then launch out of the laboratory complex and dock with Mira's ship, a General InfraDynix Hypersystems military-spec Pulse-pump Cannon Class Interstellar Battle Corvette. Once they have time to breathe, Mira and 2-Jason force 3-Jason to take a good long think about his traumatic memories -- and to realise that they contradict his memories of being transported away from Earth and celebrating his 21st birthday on an alien world. The memories that drove him to despair were implanted during his conditioning in the model house; the people who gave him his new body intended to turn him into a slave, and if he ever started to think too hard about his conditions, the false memory would be triggered to leave him depressed and once again compliant. In order to snap him out of it completely, 2-Jason tells 3-Jason to remember Benny Summerfield, and 3-Jason is nearly overwhelmed by a sudden flood of real memories. MIra deletes her personal files from her data-pad and gives it to 3-Jason, who goes into the back to write down his memories and sort them into a coherent narrative.
Mira sets off for the Braxiatel Collection to find out what trouble the original Jason is in, and if it's got anything to do with the act of genocide that ended the war between the Draconians and the Mim. 2-Jason, who wants to avoid the Collection, asks her to drop him and 3-Jason off in the Proximan Chain, a set of artificial habitats connected by a teleport transit system. After setting up base in a long-term storage locker, 2-Jason sets off to look for a way to make money, but is waylaid by a stunningly beautiful woman named Ophelia Cholmoldly-Shrike, who greets him by name even though they've never met before. 2-Jason accompanies her to her home, a stunningly opulent mansion in a private pressurised dome, where he learns that she's a fan of Jason Kane's xenoporn novels. She's also the daughter of a vicious and overprotective crime lord, which puts 2-Jason in an awkward position when Ophelia's parents come home to find him in their daughter's boudoir and their daughter dressed in a spiky leather outfit and holding a riding crop. 2-Jason barely makes it out with his life.
Meanwhile, 3-Jason has been writing down the story of his introduction to Bernice Summerfield. Oddly, he remembers himself as looking different, as though he was being played by a different actor at the time; this and other inconsistencies imply that someone else had mucked about with the original Jason's memories even before he cloned himself. 3-Jason still remembers the horrifying abuse he suffered at the hands of his father, and realises to his shame that he'll never know whether his little sister Lucy survived after he ran away. What really angers 3-Jason is that original Jason passed on these traumatic memories but kept the memory of his first night with Benny to himself, for which 3-Jason hopes his original self gets torn apart by wild dogs. 3-Jason finally finishes his story, and although he has the impression that someone else was there with him and Benny, his memories have been doctored so that he can no longer remember who it was. In any case, by the time 2-Jason returns to the storage locker, 3-Jason has finished sorting through his memories and has worked out what's really going on. The Jasons are no longer of two minds about how to deal with the situation.
Mira finishes working with the original Jason and returns to check on the others, but they've had time to prepare for her, and the moment she steps into the locker she's frozen in place by a set of stasis emitters. The two Jasons are now working in harmony, and soon they'll be fully integrated into one being, Jason-2, instead of being two separate minds in a single body as they have been all along. The truth is, even though two of them made it to the Catan Nebula, it was already too late for the first of them, and his mind burned out as it was being transferred into his new body. The same thing would have happened to the only surviving clone if he'd waited for the engineers to build a second body, so instead, they merged his mind with the fragmented one occupying the only body they had available. This created a single entity with some areas of overlap, and the two Jasons have been integrating themselves into one ever since. However, it didn't occur to Jason-2 at the time that he was placing his future in the hands of shady back-alley marketeers -- and once he was the only clone remaining, there was nobody else around who would care if they decided to turn him into a genetically engineered slave instead. It was just good luck that Mira mistook his distress for the original Jason's and showed up to rescue him.
Apart from Mira's arrival, however, the clones have been having a statistically improbable run of terrible luck. Their first clone bodies wore out more quickly than expected; the only survivor was nearly transformed into a compliant slave; the labs where he was being conditioned were attacked by fanatic killers; and most implausibly of all, even after escaping all of that, he just happened to encounter a crazed fan who could have gotten him killed, and who somehow recognised him even though his current clone body is physically 15 years of age. It's as if the universe is out to get him. Jason-2 now reveals that he reconstructed the personal files that Mira tried to delete from her data-pad, and was able to follow her subsequent exploits through her psionic implants. He now knows that someone with the powers of a god really is out to get the original Jason, and that Mira was working with him. MIra goes into such a state of denial that her mind nearly burns itself out, but the monitoring devices that Jason-2 has set up in the locker identify the affected part of her brain, microsurgically burn it out and replace it with healthy tissue. When Mira recovers, she is no longer affected by the compulsion to obey Jason's enemy.
Jason-2 reveals that his original self didn't just create clones as part of a scam; even at the time, he suspected that something was going on, and he was creating backup copies of himself in case something happened to him. Jason-2 has been playing Mira along ever since she showed up to rescue him, because he clearly remembers that she died saving his life during the Occupation. The fact that she's alive now indicates that history has been changed -- and the man who changed it planted compulsions in her mind at the same time, so that she reported back to him on the progress of Jason's investigation without realising that she was selling Jason out. Mira is horrified to realise what she's done, but when she and Jason-2 try to contact the Braxiatel Collection, they find that there's no record of either a Jason Kane or a Bernice Summerfield ever having been employed there. Whatever was going to happen has already happened, and if they go storming in now with no real idea of what's going on, they'll probably just get themselves killed. Since Jason created his clones so that a part of him would survive, Jason-2 decides to honour that by going off and living his own life rather than getting himself killed in a futile gesture.
Decades later: Mira and Jason-2 have lived long and reasonably happy lives together thanks to their continuing Plague Dogs scam. There is in fact no such thing as the Plague Dogs criminal gang; it's just a series of rumours that Jason-2 and Mira have spread, to create a fictional organisation with a reputation that they can use as and when necessary. Their relationship has survived because it's based on love, not sex, although they have had a few children together. Eventually, however, their ship is tracked down by an EarthSec Star Sentinel, and Jason-2 is dragged back to Earth to meet the President -- a clone of Bernice Summerfield who is now going under another name. One thing leads to another, and it's not until the next morning that the President explains to Jason why she's brought him to Earth. He assumes it's because she needs his help to find the original Benny, but the President reveals that they've already found what's left of her...