In a vibrant South Korean city, two siblings, Min-soo and his little sister, Soo-jin, are about to experience a summer that will change their lives. The story begins when Min-soo, an adventurous young man, discovers that his sister is on the brink of her first love. With his adolescent world filled with emotions and challenges, Min-soo feels the need to protect Soo-jin, but he also wants to help her navigate this new and exciting chapter.
As Soo-jin's relationship with her crush blossoms, Min-soo finds himself caught between his protective instincts and his desire to give her the freedom she needs. With hints of comedy and moments of tenderness, the film immerses the viewer in the antics of this sibling duo as they both deal with their own fears and insecurities. There are laughs, but also moments of tension, especially when Min-soo begins to question his own feelings about love and family.
Through hilarious adventures and life lessons, the siblings face misunderstandings and unexpected revelations, leading them on a journey toward maturity. Amid secrets, disappointments, and touching moments, each learns that personal growth often comes with the understanding that letting go is part of loving. The film culminates in a beautiful conclusion that celebrates the bond between siblings and the magic of first experiences.