Se-Jun Yoon, who has returned to school, is disappointed that the man he met by chance on the road looks like Seong-Jae, whom he had a crush on when he was young, and talks to him, but is not. After that, at a drinking party with the department, Se-jun hears that a man who resembles Seong-jae is a school idol 'Jin Do-won' with excellent grades, appearance, and personality. That day, Do-won takes Se-jun, who is drunk, to his house and has a relationship, and the next day he makes a suspicious proposal to Se-jun, who is surprised. That's right, dating example, practice, practice! Se-Jun, who is amazed, thinks Do-Won is a madman, and on his way out of the house, steps on an expensive watch that fell on the floor and breaks it...?!