stardate: unknown. The Voyager crew are research subjects after scientists of the Voth race discover the human remains of a former crewman and finds a genetic pattern similar to their own. When the chief researcher suggests that the true origin of the Voth is Earth, he seeks to prove his theory by tracking down Voyager to take Chakotay as their research subject.

stardate 50912.4. One by one, Janeway's crew suddenly and mysteriously trades places with Mercurial aliens from Nyria Three. As Janeway quickly becomes surrounded by these seemingly perplexed strangers, she must scramble to keep control of her ship. Meanwhile her confused crew is transplanted to an idyllic yet artificial world.