Mei Tachibana is a high school girl who has spent years building walls around herself. Convinced that friendship inevitably leads to betrayal after a painful experience in her childhood, she isolates from her classmates, offering only silence where others offer conversation. Her solitary existence is disrupted when she accidentally kicks the school’s most popular boy, Yamato Kurosawa, down a set of stairs. Instead of reacting with anger, Yamato is intrigued by the girl who dared to be different from the crowd that constantly clamors for his attention. He begins to chip away at her defenses, and soon the two enter into a tentative romantic relationship that forces both of them to confront their vulnerabilities.

The story is set primarily on the grounds of a typical Japanese high school, where social status and peer perception dictate daily life. As Mei steps out of the shadows and into a relationship with Yamato, she discovers that human connection is a complicated, messy affair. She must learn to navigate the turbulent waters of jealousy, insecurity, and the fear of being hurt again. Simultaneously, Yamato’s perfect, easygoing facade begins to crack as his own past, including a former friendship tainted by his inaction in the face of bullying, comes to light. Through their relationship, Mei slowly gains the confidence to form new bonds, befriending classmates like the kind-hearted Asami and the blunt but loyal Aiko, expanding her world beyond the narrow path she had set for herself.

Key narrative arcs include the challenges posed by a stalker, which leads to Yamato’s impulsive first kiss with Mei, and the arrival of other potential romantic interests that test the strength of their new relationship. The story also gives significant focus to supporting characters, such as the aspiring model Megumi who attempts to drive a wedge between the couple, and Kai, a boy from Yamato’s past who shares a unique bond with Mei over their mutual experiences of being outcasts. As the live-action film compresses the long-running manga series into a limited runtime, these arcs unfold rapidly, showcasing the highs and lows of first love as Mei learns to finally trust another person and say the words she had sworn never to speak.