Seventeen-year-old adolescence Woo Min is on his own and lives with Soo Jeong who used to be his parents' caregiver. Woo Min secretly grows fond of Soo Jeong who can't speak but finds out she's sick and feels the urge to protect her... However, as a poor minor, there's nothing he can do let alone pay her medical bills. One hot season, Woo Min sets off for a cruel world to save her.

Two spies share a secret bond, despite their loyalties. A North Korean assassin is sent to Seoul to kill a dissident, but instead he teams up with a South Korean agent in search for revenge.