The Return of Lindsay Ballard to the Starship Voyager

Ensign Lyndsay Ballard (Kim Rhodes) died on an away mission, but that doesn't stop her from returning to her home - the Federation Starship Voyager - commanded by Captain Kathryn Janeway, played by Kate Mulgrew, who also plays Russian prison cook Red on, Orange Is The New Black.

Ballard is back, but she's not the same woman.  She has been resurrected from the dead and both surgically and genetically transformed into a new species by the Kobali - an alien race who scavenges corpses and gives them new life.  Harry Kim tries to kindle something of a romance with the new Ensign Ballard, but the pull of her new race is too strong for them both.  This is one of the most poignant tales of doomed romance on any of the Trek shows.  It's all the more compelling because of the excellent performances of actors Garrett Wang as Harry Kim and Kim Rhodes as Ballard.