While flying a Jumper home from a research outpost, John Sheppard is abducted by a group of wandering space-travelers. Aboard one of their huge but dilapidated vessels, the ship's second-in-command, a man named Silas, beats up Sheppard, hoping to discover where he's from.
When that doesn't work, the ship's commander, a hard-edged woman named Larrin, tells Sheppard that her people became perpetual space-dwellers long ago to avoid the Wraith. Now, with their fleet growing too decrepit to support them, they need Sheppard's help. They've discovered a derelict Ancient warship, and because Sheppard possesses the Ancient Technology Activation gene, he's the only man who can get it running for them. By way of incentive, Larrin adds that if Sheppard won't cooperate, she'll jettison him into space.
Sheppard, Larrin, Silas and a scientist named Nevik board the Ancient warship. It suffers from a massive radiation leak, but Larrin has put up shields to protect key areas of the ship from the deadly emissions. On the bridge, Silas and Nevik order Sheppard to activate the ship. Sheppard complies, flying it forward with a jerk that sends his guards careening into walls. He ties them up and jumps the ship into hyperspace. Soon, however, Larrin exposes the bridge to the lethal radiation, forcing Sheppard to drop out of hyperspace and surrender to her if he wants to live.
Left behind by the hyperspace jump, the rest of Larrin's fleet starts tracking her down. Similarly, in Atlantis, McKay discovers an S.O.S. signal that Sheppard has rigged the Ancient ship to broadcast, so a rescue party departs immediately to its coordinates.
Unfortunately, a Wraith ship spots the signal, too, and attacks. Larrin reluctantly frees Sheppard so that he can fight back using the Ancient ship's weapons. He destroys the Wraith ship, but not before it knocks out the Ancient ship's hyperdrive and kills Silas and Nevik.
Now stranded and alone, Sheppard and Larrin are stuck in a tense stalemate, both hoping that their own rescuers arrive first. Sheppard takes over the ship's control room, but Larrin flees into the bowels of the ship. There, she comes face-to-face with a Wraith intruder, part of a boarding party that escaped the Wraith ship before its destruction. Sheppard saves her, but a life-signs detector reveals that more Wraith are also onboard. Outnumbered by their mutual enemies, Larrin and Sheppard must now work together even if it kills them - and it might.