Trials and Tribble-ations Star Trek: Deep Space Nine : Season 5 Episode 6

Stardate: 4523.7. In this celebration of the 30th anniversary of The Original Series, the disgraced Klingon spy Darvin travels back in time to undo his century-old defeat by James Kirk. The DS9 crew must track him down and stop him, while blending in with the crew of the original Enterprise NCC-1701.