As the crew tries to adjust to the merging of Starfleet and Maquis personnel, the differences are apparent. One heated procedural discussion in Engineering ends with Lieutenant Carey in Sickbay with a broken nose thanks to B'Elanna, who later gets a little advice from Chakotay on getting along and controlling her temper.

While Janeway seeks to fill the many still-vacant jobs on board, Neelix and Kes volunteer to serve -- he as a cook and guide, and she as a gardener of airponic vegetables necessary in order to conserve precious replicator power. Voyagermust make do with its Emergency Medical Hologram Doctor (designed for only short-term emergency activation), with Tom Paris assisting him. Chakotay recommends B'Elanna as Chief Engineer and Janeway agrees to consider it.

Suddenly the ship is jolted. Voyager has come upon a quantum singularity -- a star that has collapsed in upon itself, creating a powerful surrounding energy field. The crew believes another ship to be in jeopardy and tries to save it from destruction, only to find themselves trapped in the singularity. Tension rises as symptoms of sickness appear aboard and the holographic Doctor
begins shrinking.

After several vain attempts to rescue the other ship, Janeway and B'Elanna discover that the other ship caught in the distortion is just a mirror image of Voyager. The rip in the singularity that they entered through must be found and exited before it collapses, forever trapping them. Using a dekion beam fired from a shuttlecraft, the Captain and B'Elanna open up the rip wide enough for Voyager to get out. Because of her tempered initiative and unorthodox efforts in saving the ship, B'Elanna gets the Chief Engineer's post, and Lieutenant Carey is among the first to congratulate her.