Chakotay, Harry Kim, Tom Paris and Neelix are taken hostage when the Delta Flyer is captured by a Borg cube. However, the cube is littered with dead drones and controlled solely by a small group of unmatured Borg children who were left behind, unworthy of re-assimilation. The underdeveloped drones attempt to assimilate their captives, while Captain Janeway sends Seven of Nine to negotiate.

After the Delta Flyer is intercepted by a Borg cube, Chakotay, Paris and Neelix find themselves placed in what appears to be an assimilation chamber. However, Kim is not with them. A dead body lies on a table in the center of the room. It is partially assimilated and its face and arm are covered with implants that appear crudely inserted.

Meanwhile, Voyager discovers that the Borg cube's propulsion system is off-line. The cube first targets Voyager's warp core and then moves to its impulse engines. While the cube's attack strategy is erratic and inefficient, Voyager capably disables the cube's weapons. Seven discovers that there are only five signatures, instead of thousands of Borg, manning the vessel.

The Borg will return the crewmembers in exchange for Voyager's navigational deflector. However, Voyager will be unable to go to warp without it. Seven tells Janeway that the Borg most likely want Voyager's deflector in order to contact the Collective because their own is damaged.

While stalling the Borg, Janeway tells them that she is sending Seven over to make sure that her crewmembers are unharmed. Aboard the Borg cube, Seven discovers that it is manned by neonatal drones, children who have not matured long enough. The children insist that the Borg will come for them once their link is re-established.

Seven returns to Voyager along with a dead body of an adult drone. She tells the Borg children that it must be examined in order to establish what went wrong aboard the ship. The Doctor discovers that a spaceborne virus attacked the drones and is responsible for their deaths. The virus never reached the developing drones because they were protected within the maturation chambers. Malfunctions caused by the deaths of the adults led several chambers to open prematurely. The Doctor also discovers that if the pathogen is revived, it could be used to neutralize the drone children.

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Wikipedia