Time Squared, TNG 2
When in doubt, go for the time travel episodes. Picard must stop a cycle of destruction, but how can he do it if he doesn’t know where the problem comes from? All he knows is that he must not abandon the ship. But why would Picard ever do that? What possible set of circumstances could ever lead Picard to abandon the ship? Oh no! I have to leave the ship at once! (Or do I?) In a word. . .far out. . .even if I never quite understood exactly how this all got solved.