Same game you mentioned in the Fermat, Huygens-Fresnel thread, presumably?
There is a GUMSHOE game called TimeWatch, about protecting history from meddling time-travellers. The game has an integral mechanic that allows PCs to use time travel to solve problems, much like the heist movie-style “We planned for this contingency in advance” flashback scenes, but with, y’know, travelling in time, instead of having thought ahead at some point in the past. If PCs get traumatized during a game, they can even nip off for a quick four-week vacation of competetive eating on a SAN-restoring cruise ship, and return to the action mere seconds after they left.