Bae Yiwoo used to be friends with a boy named Park Jimin. They had a friendship that couldn't be broken, but Yiwoo ended up moving away to America. They kept in touch, but as time went on, they forgot about each other. Yiwoo finds an old box filled with her memories with him, and she remembers. She ends up traveling back to Korea to see if she can find him. She moves to Korea to find her old friend, but was he only just a friend to her?