In the year 2006, Satoru Fujinuma is a 29-year-old struggling mangaka in Chiba who occasionally experiences a phenomenon he calls "Revival": when a fatal incident is about to occur near him, he is sent a few minutes back in time to prevent it. He uses this to save a boy from a runaway truck, though he is hospitalized for a few days as a result. As he recovers, his co-worker, Airi Katagiri, praises him for his life-saving efforts. Later, he is visited by his mother, Sachiko, who reminds him of an incident that happened 18 years ago in their hometown in Hokkaido: an adult named Jun Shiratori (nicknamed "Yuuki"), whom Satoru had trusted, was arrested for the kidnapping and murder of three local children (two of which were Satoru's classmates). The next day, as Satoru experiences another Revival, Sachiko takes note of a man who seemingly attempted to kidnap a child. Looking into the matter, Sachiko deduces that the man was the true killer from 18 years ago, but before she can inform anyone, she is murdered in Satoru's apartment. Just as Satoru discovers Sachiko's body and is accused of killing her, his Revival sends him all the way back to 1988, when he was a 10-year-old elementary school student in Hokkaido.