Eighteen year-old Tae-hoon and Mi-jung have been going out for 100 days. During winter break they decide to take a trip to the beach to celebrate their anniversary. When they are back home after a few days, they have to confront a harsh situation – Mi-jung’s parents don’t allow them to see each other until they become college students. Tae-hoon struggles to keep their love and wanders around Mi-jung but she is eventually changed and avoids him as her parents wish. Winter turns to spring, and Tae-hoon and Mi-jung both turn nineteen.