Warning: This article contains spoilers for About Time.About Time is a sci-fi rom-com that includes one of the most interesting sets of time travel rules in fiction. Starring Domhnall Gleeson and Rachel McAdams, About Time tells the story of a young man who finds out his family has time-travel powers. More specifically, all men from his fathers side of the family can go back in time. While Tim and his father cannot travel to the future, they can go to the past, make whatever changes, and then return to the present. As soon as Tim learns about his powers, he begins to use them in his favor.

https://screenrant.com/about-time-movie-sci-fi-travel-past-rules-good/