Approaching her 18th birthday, Yoshika grapples with academic struggles and turbulent home life, feeling uncertain about what lies ahead. Amidst this turmoil, she encounters a street performance involving a 'punching bag' with a unique offer: earn 100 yen for each successful punch. Intrigued by the premise, Yoshika decides to take on the challenge, setting off a chain of events that significantly alter the course of her life.