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.