One of Jean-Claude Van Damme's best flix has his employed by an agency that uses time travel to prevent others from maqnipulating time for their personal gain. In this case it's evil politician Ron Silver.
The only Trek flick I could ever really watch more than once. A funny outing about returning extinct whales to the 1980s so that they in turn could save the earth from alien destruction. That's humans for ya. It's always about us, us, us.
This time Van Damme has been replaced by Jason Scott Lee who bounces all around time as he answers the question, should you go back in time and kill Hitler? Not the best movie you'll ever see but I liked it and I don't feel the least bit guilty.