Voyager's sensors detect the debris field of a Borg vessel. The field contains a neural interlink frequency which induces Seven to suffer multiple personality disorder, the result of her Borg implants storing the neural patterns of lifeforms assimilated by the Borg. The source of the interlink frequency turns out to be a Borg vinculum, the processing device that interconnects the minds of drones on a Borg cube. It is sending a damaged signal to Seven and needs to be taken offline. The vinculum is taken on board and found to be infected with an alien virus created by Species 6339 that is attacking the Borg technology. Torres and Tuvok target the vinculum's transneural matrix with a dampening field, but it adapts to the technology and returns to full power. The captain of a Species 6339 vessel demands the return of the vinculum. They unleashed the virus with the intention of spreading it to all Borg cubes, and plan to return it to the debris field where the Borg will retrieve it. Janeway refuses to do so until Seven has been cured. The alien vessel fires on Voyager. Torres remodulates the dampening field and finally manages to disable the vinculum. Once it is beamed into space, the alien vessel ceases its attack. All of the other neural patterns in Seven's mind become dormant.

Neelix asks permission to replicate locking mechanisms for the messhall cabinet doors due to thefts by the "midnight snacker".

Voyager is fired upon by vessels of Species 6339.

There are 47 suborders of the Prime Directive.

Among the personalities exhibited by Seven are Ensign Stone of USS Tombaugh (commanded by Captain Blackwood - the Borg assimilated his vessel 13 years ago), and the mother of Lieutenant Gregory Bergan of USS Melbourne (who was assimilated at the Battle of Wolf 359).