First Contact: 'A Matter of Time' Season 5 Episode 9

While the Enterprise tries to save a planet suffering from an environmental disaster, a historian, apparently from the future, arrives on the Enterprise to observe the events. His eccentric manner infuriates some of the crew, except Doctor Crusher, but I’m not sure what they were trying to do there. Anyway, they save the planet with some phasers and deflectors because they can solve all problems and the time guy is revealed to be a con artist from the past. And that’s about it.