Pharmaceutical researcher Kazuko Yoshiyama has privately discovered a formula for time travel when she is left unconscious after a car accident. Her daughter Akari, on the belief that finding her mother's first love - Kazuo Fukamachi will enable her mother to wake up again, uses Kazuko's formula to leap back in time from 2010 to the 1970s in hopes of seeking younger Kazuo. Unfortunately, Akari finds herself traveled to a wrong year: 1974 instead of 1972, so she meets and befriends Ryota Mizorogi, who lets her stay in his flat and help her to find Kazuo. The future becomes uncertain as the duo realize they fall for each other.