Dylan and Trance watch in horror as the mortally wounded Arkology spills the fragile living detritus that once lived safely inside. Trance argues that Dylan may be the only one who can get through this alive, the Route of Ages being his safe exit and no one else's, but he is adamant about rescuing the survivors from the fate of being living incubators for the Magog.

The crew struggles over their options as the Magog prepare another assault. Though the Arkology's resealing system has kicked in, the concern is whether the ship will hold together while in Slipstream. Harper and Rommie wrack their brains for a solution, while Dylan and Trance consider the total destruction of the worldship. Such violence would wipe out any prisoners and other entities aboard, but there may be little choice. Swarm ships beset the Arkology, and the residents make a feeble attempt at defending themselves. The crew intends to buy time by retreating to the Andromeda with as many people as they can take with them, but Rhade refuses to leave, choosing instead to meet his fate with Louisa and her people. He gathers as many as he can in the grotto and gives them a crash course in combat. Beka, who is ready to flee the whole scene, checks with Harper one last time, then takes the Eureka Maru to Slipstream.

Dylan watches the Magog orchestrate yet another massive assault. He decides to use the Andromeda to take some of the heat off of the Arkology. He contacts Harper, who cannot leave but suggests temporarily increasing the gravity aboard the giant settlement Ñ a tactic that pins the enemy to the ground and buys everyone some time. As the Andromeda moves away, swarm ships attack and begin to punch through the outer skin, while Slipfighters pick off what they can. Rhade, meanwhile, fights the Magog with the citizens in the grotto. He and Louisa finish off one wave and turn to face another, when the enemy is suddenly stuck in the tracks. Harper has increased the gravity, but Rhade, being a heavy-worlder, is still capable of movement, albeit hindered. Harper calls Rhade to his position, where the gravity is normal, but fails to see a Magog that has crept up behind him. Rommie attacks the Magog, wrapping her hands around his throat Ñ but he gets a shot off point blank into her torso. Rommie kills the warrior, then turns to Harper with a huge hole in her belly. He watches her explode.

Trance and Dylan learn of the halted Magog assault, but the Andromeda is overrun, and the pair is cornered in the weapons locker. As the enemy blows open the doors, the duo escapes through a conduit, with Dylan ordering Andromeda to arm and fire all nova bombs at the Magog worldship. The worldship suffers minor damage, slows down slightly, then simply unleashes a torrent of swarm fighters directly at the Andromeda.

Beka bursts back on the scene just as Harper disconnects the main Arkology structure from its anchored asteroid and moves it toward a Slipstream portal. Rhade and Louisa see that it has begun to move but is breaking apart. Suddenly, they are ambushed by the Magog and their leader. They fight until Louisa falls. Rhade rushes to her and holds her as she dies, then stands to meet his fate against the remaining Magog, who open fire on him.

Dylan and Trance are trapped in the conduit; the entire Andromeda crew is dead. He orders the ship sealed off and all life-support terminated except for the section he and Trance occupy. When the intruders are all dead, he and Trance make their way to the hanger. Trance convinces him it is time for him to leave. If he were to stay, she says, dying to win the battle, the war would still be lost. He must take the Route of Ages by himself; she cannot go with him and still perform her function here. He kisses her goodbye and takes off in a Slipfighter.

The Arkology is almost to the open Slipstream portal when it breaks apart completely. Trance turns the Andromeda toward the worldship and unloads the remaining ordnance into it. Beka spots Dylan and escorts him for a moment. After their brief goodbyes, she turns toward the Arkology wreckage. Harper is still alive aboard the drift. Beka tries to locate him before communication is cut off and she is lost amid the swarming Magog ships. Harper crawls from his hiding place but is ambushed by the Magog leader, who lunges for his throat.

Trance tries one last time to speak with the Andromeda A.I., but the ship is too badly damaged. In a supreme sacrifice, Trance Ñ the avatar of the sun Ñ reaches the worldship and goes supernova, turning the Andromeda into an immense, fiery mass. It crashes into the worldship and disintegrates it, sending millions of pieces flying in all directions.

The Route of Ages looms in the window of Dylan's Slipfighter and he dives through it. He finds himself in another dimension filled with infinite blackness. Climbing from the cockpit, he sees a pinpoint of light winking in the distance Ñ and he smiles as he steps into his future.