Iwase Ken and Yoshida Rei have been friends since elementary school. Ken, is obstinate and unskilled in love, but he fell long ago for the lively and cheerful, Rei. But Rei is about to get married to another man. While Ken and other friends from high-school attend the wedding ceremony, a fairy appears and sends Ken back in time, giving him a second chance to win the girl he loves.
Ken returns to their past celebration of new year's eve. He intentionally let his friends go and see the new year's sunrise by themselves, hoping that he would forget all about Rei.
Ken returns to the last photo of the slideshow where they are in Tada's party, Tada introduces Rei to all his friends. In the middle of the event Ken dragged Rei into their elementary school.
Ken returns to his highschool graduation where boys give their second button to the girl they like. He gave his button to another girl making Rei disappointed. He gives his best shot in order to touch Rei's heart.
Ken returns to just before Rei's birthday and also on her eve of her major architectural project.
Ken returns to just before Tada proposes to Rei.
Ken plans to have a "coming from behind victory" over Rei, but as he heard Rei's opinion about regrets, Ken decided not to change the past but to act in the present. So Ken returns to just before he has to give a speech at the wedding banquet.
Ken rushes to Rei's wedding and through the ceremony he suffers regret at never being able to articulate his feelings. A magical being in the church takes pity of him and allows him to "time slip" through certain photos. This gives Ken a second chance to relive key moments in his lives. Initially Ken returns to the final game of the season where he has another opportunity to win the game and make the playoffs.
The photograph on the slide show showing an angry Rei bothered by Ken. He returns to the past where Rei asked him for a coffee milk. He thought, this coffee milk was his way of changing his present and making him the man who sits beside Rei.
Ken returns to the past wherein they met Tada-sensei, Rei's groom. Ken tried his very best to avoid making Rei and Tada-sensei close. But in the end, it was Tada-sensei who made him see the smile he never saw 6 years ago.