Satoru Fujinuma is a struggling manga artist who works at a pizza parlour. Ever since he was a kid, he has been holding himself responsible for a kidnapping incident and finally the time has come for the truth from his past to be revealed.

After Satoru discovers his mother brutally murdered in his apartment, he goes back 18 years in time, before classmate Kayo's kidnapping and murder.

As Satoru relives his childhood days at school, he befriends Kayo and stays by her side on March 1 to thwart the kidnapping that would take her life.

Satoru invites Kayo to the Science Centre so she won't be alone, as he suspects that he's riding the same pre-Revival rail of time, and before he knows it, X-day has arrived.

Satoru meets with Sawada, a former colleague of his mother, who is also looking for a connection between her murder and the kidnappings from the past.

Kayo shows her friends the bag that the angry stranger stashed inside the bus. Inspired by Satoru, his mother and teacher take action to help Kayo.