In the year 2006, Satoru Fujinuma is a 29-year-old manga artist who experiences a phenomenon known as "Revival," in which he is sporadically sent back in time by a few seconds, allowing him to perform life-saving feats. He uses this to save a boy from a runaway truck, whose driver had died from a heart attack, though becomes hospitalized for a few days as a result. As his co-worker, Airi Katagiri, praises Satoru for his life-saving efforts, Satoru is visited by his mother, Sachiko, who reminds him of an incident 18 years ago in which an adult named Jun Shiratori, who Satoru had trusted, was arrested for the kidnapping and murder of two of his classmates. The next day, as Satoru experiences another Revival phenomenon, Sachiko takes note a man who seemed to be trying to kidnap a child. Looking into the matter, Sachiko deduces that the man was the true killer, but before she can inform Satoru, she is killed in Satoru's home. 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 still an 11-year-old elementary school student.