Star Trek: Voyager - Season 5 Episode 11 -

The Doctor uncovers evidence his memory was erased 18 months ago. Nearly all traces of a crewman and a fateful away mission have been deleted by Captain Janeway. Confronted by The Doctor's need for answers and Seven of Nine's perspective on the rights of a hologram, Janeway restores the fatal truth about Ensign Jetal, The Doctor's choice that led to her death, and his resulting breakdown.