Yeo Reum who just got her first job is Ji Hun's girlfriend. Ji Hun who doesn't have a specific job is a member of a band named Yellow. Yeo Reum is a realistic girl who works hard to be a decent grownup and she finds it hard to understand Ji Hun who has nothing but only Yeo Reum in his mind. One day, Ji Hun notices that Yeo Reum decided to break up with him and goes to meet her, and she really breaks up with him there. Ji Hun spends a year missing Yeo Reum, and one day, he receives a message from Yeo Reum.