Plot summary
Aboard the Delta Flyer, Seven of Nine, the Doctor, and Ensign Harry Kim, encounter the Lokirrin species. The Lokirrin experienced an insurgency by their holograms, and therefore harbor prejudice against all photonic beings. The Lokirrin detect the Doctor and board the Delta Flyer; they capture Seven and Kim, but the Doctor is nowhere to be found. Seven reveals to Kim that she is the Doctor—Seven downloaded his program into her Borg implants, and he controls Seven's body. As Seven, the Doctor interacts with several Lokirrin crew, and their captain Ranek is attracted to her.
Aboard Voyager, Tuvok has started going through Pon Farr (the seven-year urge to mate). When the planned treatment does not work Tom Paris (standing in as medic in the Doctor's absence) creates a hologram of Tuvok's wife on the holodeck.
The Doctor temporarily grants Seven possession of her own body. Seven protests his indulgence in food and sexual arousal while controlling her body, but the Doctor argues such sensations and emotions make life worth living and she shouldn't deny herself them. Meanwhile, Voyager encounters a different group of Lokirrin and Captain Janeway agrees to shut down holodeck activities while in Lokirrin space; unfortunately this interrupts Tuvok's holodeck treatment.
The Doctor (in Seven's body) sedates Ranek during a date and contacts Voyager. In the ensuing conflict with Voyager Ranek is injured. The Doctor reveals he is a hologram and treats Ranek, showing the Lokirrin that not all photonic beings are villainous.
Back aboard Voyager, Seven brings a meal to sickbay and describes the sensations she feels eating it allowing the Doctor to enjoy it vicariously. Tuvok completes his holodeck treatment and thanks Tom for his help while also making it clear the hologram could not replace his real wife.
Credits
Adapted from Wikipedia contributors, Body and Soul (Star Trek: Voyager). Paragraphs and formatting adjusted; illustrations, reference markers, block quotations and non-story material omitted.