The Imperial prison barge Purge, temporary home to five hundred of the galaxy's most ruthless killers, rebels, scoundrels and thieves, breaks down in a distant, uninhabited part of space. Its only hope appears to lie with a Star Destroyer drifting nearby, derelict and seemingly abandoned. When a boarding party from the Purge is sent to scavenge for parts, only half of them come back, bringing with them a contagion so lethal that within hours, almost all aboard the Purge are dead - the half-dozen survivors are two teenage brothers, Kale and Trig Longo, a ruthless captain of the guards, Jareth Sartoris, and the chief medical officer, Zahara Cody, all of whom seem to possess natural immunity.
The Purge's onboard computer informs Cody that there are also two survivors in isolation, and Cody leaves the medibay to release them and administer an antidote synthesized from her blood by the incumbent 21B medical droid "Waste". The isolated prisoners are Han Solo and Chewbacca who initially are skeptical of the situation, however allow her to immunize them, and make their way back to medical. Upon returning to medical they find it empty, and Waste destroyed. The dead have become undead and begin to hunt the survivors who are forced to abandon Purge and take shelter in the