Saving Time

From BoardGameGeek:

Saving Time is a cooperative time travel game in which players embark on a mission to correct historical aberrations (crises) created by a alien race whose sole goal is to weaken modern civilization. By use of actions, players move through history, playing and collecting both cards and tokens in order to correct aberrations and to reveal information about the aliens in order to defeat them. Saving Time plays 1-4 players.