Star Trek: Voyager (1995)

S01E08 Emanations

Stardate: 48623.5. A mishap with the transporter results in Harry Kim switching places with a terminally ill woman from a parallel universe. Harry is thrust into a world of aliens who think he has come back from their version of the afterlife. Meanwhile, the woman, anticipating a blissful existence, finds herself aboard the Voyager, confused by her new surroundings.