Jung Soojung is entering her last year of high school, and wants nothing more than for it to end already. She wants to grow up and be successful like her older sister, Sooyeon. She loves her friends and family, but she wants to live her life how she wants to. Then she meets Amber- the exchange student from America. She and Soojung slowly go from acquaintances to friends, and after spending time together, they become closer than either of them could have ever imagined. Suddenly Soojung doesn't want to grow up so fast anymore- she doesn't want the period between graduation and college to ever end. But by the time she figures it out, it's too late, and she has to say goodbye to summer.