Again

The main character, Imamura, is a student attending his high school graduation. Due to his appearance and personality, he didn't make a single friend during his three years of high school. As he remembers his school days, he wonders what his life would have been like if he had made different choices. In particular, he wonders about his life had he answered yes when a girl from the cheering club asked him to join. Since the cheering club was disbanded, he feels he should take one last look at the club room before leaving the school forever. However, he is misunderstood by another girl who is waiting for her boyfriend, and as he chases her (to clear up the misunderstanding), she falls down a flight of stairs (possibly dying). He goes to check on her but ends up falling too. He wakes up to find he is back to his first day in school (three years ago). Thinking it's obviously a dream, he just tries to correct the mistakes he made during that day...until the girl shows up blaming him for pushing her down the stairs and what's worse - bringing her three years into the past!