In Japan, 11-year-old Punpun Onodera, a dreamy and sentimental boy, experiences a shift towards adulthood after encountering his new classmate, Aiko Tanaka. Through their relationship, he discovers the complexities of growing up and the harsh realities of maintaining connections. Witnessing his father's violent act against his mother shatters Punpun's idealizations of his role models. As challenges mount, Punpun retreats into isolation, grappling with unresolved emotions and inner turmoil. This poignant tale delves into the tumultuous journey from innocence to the somber complexities of maturity.