Shouya Ishida, a mischievous elementary school student, finds himself troubled by deaf transfer student Shouko Nishimiya. Despite her genuine attempts to befriend her new classmates, Shouko only proves herself to be an annoyance for Shouya and his friends, provoking them to ridicule her at any possible chance. Soon enough, their taunts turn into constant assault—yet the teachers heartlessly remain apathetic to the situation.

Shouya's misdeeds are finally stopped when Shouko transfers to another school. Denying their involvement, the entire class puts the blame on Shouya. As the new victim of bullying, Shouya gradually becomes meek and reclusive, being treated with contempt and disregard for years to come.

Now a high school student, Shouya meets Shouko again for the first time in five years. Still tormented by his past actions, Shouya is determined to make amends for his mistakes and confront his trauma—even if he must face arduous obstacles along the way.