Kosuke and Mao were classmates in the Junior High School and they were also each other's "first love". However, their relationship was ended when Kosuke transferred to another school. Since then they never contacted each other again.
After decades apart, childhood friends Nora and Hae Sung are reunited in New York for one fateful weekend as they confront notions of destiny, love, and the choices that make a life.
Hiroko attends the memorial service of her fiancé, Itsuki Fujii, who died in a mountain-climbing incident. Although Itsuki's mother says that their old house is gone, Hiroko records the address listed under his name in his yearbook and sends him a letter. Surprisingly, she receives a reply, and discovers it came from his old classmate, a girl who also happens to be called Itsuki Fujii.
Sarah and David are single strangers who meet at a mutual friend’s wedding and soon, through a surprising twist of fate, find themselves on a funny, fantastical, sweeping adventure together where they get to re-live important moments from their respective pasts, illuminating how they got to where they are in the present... and possibly getting a chance to alter their futures.
At Kichijōji Station, Tokyo, Taku Morisaki glimpses a familiar woman on the platform opposite boarding a train. Later, her photo falls from a shelf as he exits his apartment before flying to Kōchi Prefecture. Picking it up, he looks at it briefly before leaving. As the aeroplane takes off, he narrates the events that brought her into his life...
Mio has long hidden her feelings for her childhood friend Arata. After an argument leaves their relationship uncertain, she sets out to reconcile with him but awakens in a mysterious version of Ikebukuro following an accident. Guided by unusual new companions, Mio searches for a way home while confronting the feelings and memories she has avoided.