Lieutenant Jaryn was a Lokirrim female who served aboard a Lokirrim patrol ship commanded by Captain Ranek. They were at war with photonic beings who had rebelled against their organic masters. When her ship encountered the Delta Flyer with The Doctor aboard, her crew demanded the ship surrender. In order to protect The Doctor, Seven of Nine downloaded his program into her cortical implant. This allowed The Doctor to control her body and experience the full range of Human sensations.
While The Doctor was in control of Seven, he met Jaryn, who took him to their sickbay. She showed him patients who were suffering from synaptic failure caused by a viral weapon from their photonic enemies. Seven/Doctor developed a treatment, got to know Jaryn better and developed an attraction for her. Jaryn told him about her family's photonic servant before the uprising. Later, when Ranek made amorous advances towards Seven/Doctor, he told Jaryn about Ranek's behavior. The Doctor subsequently learned that Jaryn was in love with Ranek. The Doctor/Seven became jealous and told Jaryn that she should find someone like him/her. When he pulled a neck muscle, Jaryn massaged his neck, causing sexual arousal in The Doctor side and angering the Seven side.
Ranek also developed a romantic interest in 'Seven', not knowing that Jaryn had a romantic feelings for him. When Ranek was severely injured during an attempt by the USS Voyager to rescue its crew members, The Doctor – released from within Seven's implants – operated on Ranek and saved his life, prompting Jaryn to reevaluate her opinion of holograms as she thanked The Doctor, complimenting his medical skills before he departed. (VOY: "Body and Soul")