Plot summary
Jack, Lauren, Patrick, and Sarina show up at Deep Space Nine, impersonating an Admiral and his staff, so that Bashir can try to cure Sarina's condition. They help Bashir refine a medical instrument so he can operate on her.
The operation is a success and Sarina is able to speak and interact with her surroundings for the first time. When she's reintroduced to the rest of her group, they try to help her feel included by starting up a sing-along. Though initially only able to sing in monotone, within minutes Sarina masters solfège and is able to improvise an a capella fugue with the others.
The quartet later is discussing the eventual Big Crunch, trying to figure out how to stop it. When Sarina argues against the feasibility of doing so, Jack shuts her down. When Bashir comes in to check on her later, she's drawn within herself, seemingly catatonic as she was before the operation; fearing the worst, he goes over to check on her. She tells him that she resumed this stance to stay out of the discussion, because she had been made to feel Jack and the others expected her to be quiet.
Bashir falls in love with her and assigns another doctor to take over her care so he can pursue her romantically. She is not ready for a relationship, and goes catatonic again after he invites her to his quarters for dinner. After she recovers, she tells him she felt pressured to thank Julian for curing her by being the woman of his dreams. At the end, she leaves DS9 for a scientific internship.
Credits
Adapted from Wikipedia contributors, Chrysalis (Star Trek: Deep Space Nine). Paragraphs and formatting adjusted; illustrations, reference markers, block quotations and non-story material omitted.