Makoto Konno a girl attending high school in Tokyo realises she has the power to go back in time and re-do things (called a "time-leap") when she impossibly avoids a fatal accident at a train crossing one day.
Bewildered, she consults with her aunt At first, Makoto uses her power extravagantly to avoid being tardy and to get perfect grades on tests, and even relive a single karaoke session for about ten hours. However, things begin to turn bad as she discovers how her actions can adversely affect others. Makoto ends up using up more of her leaps to recklessly prevent undesirable situations from happening, including an awkward confession of love from her best friend Chiaki Mamiya . Eventually she discovers a numbered tattoo on her arm which counts down with each leap. She determines that the tattoo indicates that she can only leap through time a limited number of times. With only a few time leaps left, she attempts to make things right for everyone, but impulsively uses her final leap to prevent a phone call from Chiaki asking if she knows about time-leaping. As a result, she is unable to prevent her friend Kōsuke Tsuda and his girlfriend from being killed in the accident at the train crossing that Makoto was originally involved in. Devastated, time suddenly stops.