Voyager beams aboard a deactivated robot which Torres repairs. The robot introduces itself as Automated Personnel Unit 3947, one of a nearly extinct line of workers created by the Pralor, a species of extinct humanoids. Concerned over the potential extinction of its own mechanical race, APU 3947 asks Torres to build a prototype power module to help with the construction of additional units. When refused due to Starfleet's Prime Directive, the robot kidnaps Torres, beaming them both to the ship, crewed entirely by similar robots, that has come to retrieve it. The Voyager crew are unable to penetrate the subspace defence shield surrounding the Pralor vessel. When Voyager fires on the alien ship, the robots respond by launching a violent attack on Voyager. To prevent Voyager's destruction, and unable to contact her crew because 3947 deactivated her combadge, Torres agrees to build the desired prototype. A second alien vessel, manned by similar robots, begins firing on the Pralor vessel, saying that Voyager will not be harmed as long as they stay out of the battle. Seeing the battle as a handy diversion, Janeway mounts a rescue mission - Paris takes a shuttlecraft through the Pralor ship's shielding and retrieves Torres.

Janeway tells Tuvok to load Torpedo Bays 1-4.

Following Voyager's encounter with the Pralor vessel, the aft shields are non-functional and propulsion systems are offline. There is a hull breach on Deck 6, artificial gravity is lost on Deck 8, environmental control systems are failing, oxygen levels on Decks 3 to 7 drop to critical, and those decks are also without power. According to the robots' sensors, it will take Voyager 140 hours (= five days) to repair the damage, although Chakotay estimates it as six days. The priority repair is the dilithium matrix that has destabilised, since they cannot get the engines running.

Concerned over the potential extinction of its own mechanical race, 3947 asks Torres to build a prototype power module to help with the construction of additional units, but Janeway points out that giving the robotic species the power to "procreate" would be a violation of the Prime Directive. When Torres later realises the true circumstances of the Pralor and the Cravic, she belatedly appreciates the wisdom of the Prime Directive.