After the Enterprise's debacle in the previous episode, "Minefield", the crew finds itself in need of assistance to effect repairs. They send a distress call, and the Tellarites send the coordinates of a station—a station capable of serving their every need at a cost which seems too good to be true.
Four days after surviving the Romulan minefield, Captain Archer and Chief Engineer Trip Tucker inspect the damage to the ship with a shuttlepod. Given the amount of damage, and the travel time to Jupiter Station, Archer decides that it is time for someone to help them out for once, and orders Ensign Sato to send a general distress call. A passing Tellarite freighter soon responds, and sends a barely understandable message directing them to an automated repair facility, three days away at Warp 2.
Upon arriving at the facility, which appears inert at first, the ship is scanned and the station reconfigures itself to suit the crew's needs. Enterprise then docks and the station computer sets the full repair price, including healing Lt. Reed's previously injured leg, at 200 liters of warp plasma, a relatively low level of compensation. And, by using its advanced replication technology, the station can complete all repairs in just 34.2 hours, whereas Starfleet's best repair teams would take months. Archer, left without any other option, agrees to the repairs.
Later, however, Archer has a gut feeling that not everything is as it appears, but he can't put his finger on what this might be. Meanwhile, Tucker convinces Reed to locate and observe the station's computer, but their attempt to enter is detected by the computer, which beams them back to the bridge. Meanwhile, a false comm message, ostensibly from Archer, directs Ensign Travis Mayweather to an area currently being repaired. He is found dead soon after, an apparent victim of an electrical shock. When Dr. Phlox discovers that the dead Mayweather isn't actually Mayweather at all, but instead a well-replicated duplicate, Archer resolves to search the station for him.
Reed leads Archer and T'Pol in the same air duct that he and Tucker used to find the computer, while Tucker delivers the plasma and 'distracts' the computer. Reed again trips the alarm, giving Sub-commander T'Pol and Archer the information needed to disable the duct sensors. They then enter a computer room filled with bodies — among which are a Klingon, a Vulcan, and a Cardassian. Apparently the computer retrieves a crew member from every vessel which docks, and wires that person to the station's brain to augment its own processing power. Mayweather is disengaged and rescued (the other victims have suffered too much brain damage and are beyond help) just as the station starts attacking the Enterprise in retaliation. Archer then detonates the warp-plasma payment to blow up the station and escape. As the ship warps away, in the aftermath of the explosion, the few active components of the station set to work repairing the damage.