Shingo, a college student experiencing his first relationship, and Momo, his modest junior, are enjoying the excitement of young love despite their inexperience. One day, Momo visits Shingos room for the first time, only to encounter an unexpected person—Shingos older brother. What begins as a seemingly harmless joke gradually crosses the line. Before long, the pure relationship between Shingo and Momo starts to drift in a forbidden direction. Amid unfamiliar temptations and growing confusion, Momo begins to change. Then, when Shingo finally returns, the relationship between the three of them reaches a point of no return.