This is a live-action adaptation of Toki o Kakeru Shōjo (The Girl Who Leapt Through Time).
When Kazuko Yoshiyama, a pharmaceutical researcher, gets involved in a car accident, she tells her daughter Akari to go back to February 1972 to find someone from her past, Kazuo Fukamachi, using the liquid she has formulated in her laboratory. A distraught Akari remembers the wrong date and returns to April 1974 instead. She befriends Ryota, an aspiring film-maker and science fiction geek, who helps in her search for Kazuo.
I hate those self-righteous fellows who insist on doing memory wipes in time traveller movies. There’s one in here. Arghh! As expected, Akari and Ryota fall in love, even though they both know Akari belongs to the future and even if they meet, Ryota will most likely be a father figure to her. The movie banks on the simplicity of life and relationships in the ’70s. Akari even meets her father, an absent figure in her current life. The saddest part (cue buckets of tears) of the movie happens when Akari views the 8mm movie Ryota directed, after she returns to the future, and she was crying even though she had no memory of what happened.