Star Trek: Voyager S03 E02 Flashback

"Charting the new frontier"

Stardate: 50126.4. After falling ill to what appears to be a repressed memory Tuvok must perform a mind-meld with Captain Janeway in order to survive. The meld takes them back to when Tuvok was a junior science officer aboard the U.S.S. Excelsior under the command of Captain Hikaru Sulu.