When a letter and cassette tape from 23 years ago show up at a radio station, the radio DJ and his old friends reminisce on the bittersweet summer they last spent together as kids. Every summer, Soo Ok patiently waits for her friends Beom Sil, San Dol, Gae Deok, and Gil Ja to arrive back to their home town island. This summer is filled with fun, romance, and tragedy.