Shoya Ishida, a mischievous elementary school student, finds his life turned upside down when Shoko Nishimiya, a deaf transfer student, joins his class. Despite her efforts to make friends, Shoko becomes the target of relentless teasing, with Shoya leading the charge. However, when things go too far, Shoko suddenly transfers away, leaving Shoya to face the consequences of his actions. Isolated and burdened with guilt, he begins to understand the pain he once caused and struggles with feelings of regret as he grows older.

Now a high school student, Shoya encounters Shoko once again after many years. Determined to right his past mistakes, he sets out on a journey of redemption, hoping to reconnect with her and prove that he has changed. Along the way, he faces personal challenges, strained friendships, and emotional obstacles that test his resolve. As he and Shoko navigate their complicated relationship, they both learn valuable lessons about forgiveness, self-acceptance, and the power of human connection.