Juyeong is in a juvenile detention center for the attempted murder of his father, Gang-ryong. He clings to hope, dreaming of a future in Seoul with his childhood friend, Dayeon. But everything shatters when Dayeon is tragically killed by a rogue truck, and the devastation deepens when Juyeong learns that his father was behind the wheel. In a cruel twist, Gang-ryong regains consciousness and offers Juyeong an ultimatum... "If you want revenge, become the king of this detention center!" Now, Juyeong must navigate the treacherous world of prison politics, determined to rise to power and avenge his friend.