Star Trek: Voyager - Season 6 Episode 23 -

Kes returns to Voyager - older, angry, and more powerful than ever. She literally tears through the ship. Using her abilities in combination with Voyager's warp core, Kes travels back in time to Voyager's first year in the Delta Quadrant. Her agenda is to kidnap her younger self and return her to the Ocampa, even if it means turning her former friends over to the Vidiians. The only one to suspect anything is Tuvok, who is experiencing intermittent visions and memories of the future.