Cheolsu, an ordinary university student majoring in journalism and communication, spends a joyful campus life with Mimi, a bold English major. One day, he meets a law student nicknamed "Treasure Island," and together they entertain those around them with their outlandish actions. Meanwhile, Mimi, considering her future, meets a medical student and decides to get engaged. However, Cheolsu suddenly appears on the scene, and she defines their relationship as friendship before turning away. That night, as Cheolsu drinks to forget his sorrows, "Treasure Island," who is with him, collapses and is hospitalized, finally revealing "Treasure Island's" secret. He suffers from an incurable brain tumor and wishes to spend his remaining time teaching people with cerebral palsy and building his life. At the request of "Treasure Island," who wants to see the sea, Mimi and Cheolsu embark on a journey. Shortly after, "Treasure Island" ends his short but passionate life at the age of twenty-one.