Boku Dake ga Inai Machi is a taut psychological thriller, about Satoru Fujinuma, a failed mangaka, who travels back in time to his childhood to stop a serial killer, but that’s not what makes it special. It’s what happens in the very first episode, after the protagonist used his involuntary time traveling powers to stop an accident from happening, only to get injured in the process himself. As he goes home from the hospital to his dinky one bedroom apartment, he finds his mother, Sachiko Fujinuma, waiting for him, having rushed over to take care of him while he’s on the mend. That’s rare; usually in anime, even obsessed with high school settings as it is, parents rarely show up, being conveniently dead, too busy with work or just plain ignored to take much notice of their children’s adventures. But here we have a mother of an adult son, who not only comes over to care for him when he needs her, but who also helps him a few days later when his powers kick in once again and it is she who, by virtue of just paying attention at the right time, who actually prevents a child abduction. Which in turn gets Sachiko wondering about those serial killings because she is sure she recognised the would-be abductor. Which of course gets her murdered quickly, with her son as the main suspect.
Don’t worry: she gets better. Or rather, as said, Satoru’s despair catapults his mind back into time from 2006 to 1988, when he was eleven years old, to just before the original serial killings took place. He now has a chance to make good the mistake he made back then, when he could’ve saved his classmate Kayo Hinazuki from being murdered, if only he hadn’t left her alone when he saw her in the park on the night of her abduction. For Satoru, his inadvertant leap back into time means a chance for redemption, a chance not just to prevent his classmate’s murder, but that of his mother as well. If he can chance the past, he can change the present he left behind. if he can change the past.
Satoru of course tries and hide the truth from his mother, but Sachiko isn’t the type to stay fooled for long. She knows her son is up to something when he suddenly starts befriending Kayo and quietly supports him from the sidelines. A single mother, she works as a news announcer and she’s smart enough to guess some of what’s happening, to be there when Satoru needs her the most. Even as he thinks he has to solve the problem of keeping Kayo save from both her killer and her own abusive mother on his own, she’s there to help. Which you could argue is the central theme of Satoru’s own character growth over the course of the series so far: learning to rely on others, especially his mother, when his problems are too big to tackle on his own.
More so than Satoru, Sachiko is the heart of Boku Dake ga Inai Machi, with her presence felt throughout the series even in those episodes she’s barely present for. It comes out in the little things, like how she greets Satoru and friends when they bring Kayo back in episode eight. Or the fact she’d already bought pajamas for her beforehand. Or more mundanely, how she and Satoru act around each other in their day to day lives, something you don’t really notice much until it’s driven home when Kayo’s there to see the contrast with her own home life. Not that you need that contrast to know that thanks to her, Satoru will always have a home to return to, a place he can be safe in no matter what happens. That’s why her murder has to be put right or the world itself isn’t right.