On his 21st birthday, Tim Lake (played by ) learns from his father (played by Bill Nighy ) a life-altering family secret: the men in their family have the ability to travel back in time to any moment they have personally lived.
Tim uses his ability to perfect his interactions with Mary, eventually winning her heart. However, he soon discovers that altering the past often carries unintended consequences for those around him.
Initially, Tim uses his gift to improve his social life and find a girlfriend. After a failed attempt to woo Margot (Margot Robbie), he moves to London and meets Mary ( Rachel McAdams ) during a "blind date" at a restaurant in total darkness.