The initial story goes back to the 1970's and has been tackled before but in the opinion of many never in quite the emotional depth of this adaptation and runs like this: Makoto Konno, a high school girl in Tokyo's shitamachi, realizes she has the power to go back in time and re-do things (what is called a "time-leap") when she impossibly avoids a fatal accident at a train crossing one day. Bewildered, she consults with her aunt throughout the film, who then implies that she is the protagonist from the original novel.
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. It isn't long however that things begin to turn bad as she discovers how her actions can adversely affect others.
Makoto soon ends up using 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 that counts down with each leap.
From this tattoo she realizes it 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 she 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. As Makoto watches the accident in horror, time suddenly stops.
Chiaki reveals that he is a traveller from the future and leapt through time in order to see a painting being restored by Makoto's aunt, as it has been destroyed in the future.
While walking in the frozen city, Chiaki hints that his original era occurs after a world wide catastrophe decimates mankind.
He then reveals that he has used his final leap to prevent Kōsuke's accident and has stopped time only to explain to Makoto what the consequences will be.
Having revealed his origins and the source of the item that allowed Makoto to leap through time, and being unable to return to his time period, Chiaki must disappear.
Makoto realizes too late that she loves him as well.
True to his words, Chiaki disappears when time begins again and Makoto is upset.
As she tries to come to terms with losing him, she discovers that Chiaki's time-leap had inadvertently restored one time-leap to her: Chiaki had leapt back to before Makoto used her last leap. Makoto now leaps to the moment when she gained her powers, at which point Chiaki still has one remaining time-leap.
She reveals everything that he told her in the future concerning his indentity, the ability to leap through time, and his reasons for extending his stay in her time frame.
Shortly before returning to his time period, Chiaki says he will wait for her in the future and Makoto replies that she will run toward it.
What makes the film so enjoyable is the portrayal of each character having many layers which adds to the sense of being able to empathize with them throughout the story which is very much bitter sweet because Makoto learns that this power has to be handled with responsibility- changing the past is not so straightforward - and that actions beget reactions as she uses it to make a new world for her friends.
I found it very moving.