Nak-hoon, a teacher at Seon-am Academy and a former resident, knows his daughter, Seon-hong, continues to associate with Seok-woo, another resident. However, he can't bring himself to tell Seon-hong not to play with Seok-woo, as Seok-woo is her only friend. But when the academy threatens to send Seon-hong to a rehabilitation center if she continues to associate with Seok-woo, Nak-hoon decides to help Seok-woo escape the island to prevent him from meeting Seon-hong.