Rengoku-Jima summary: Jin-Yi Hak killed five men and called it justice, the world called it murder. Now he's trapped on Rengoku-jima: a brutal prison island reserved for society's most dangerous criminals, a place said to be far worse than hell itself. Forced to navigate a ruthless environment where the lines between punishment and survival blur, he must endure the psychological and physical horrors of the island. Surrounded by danger at every turn, Jin-Yi Hak's fight for survival begins as he confronts both the monsters around him and the dark reality of his new environment. Amidst the violence and psychological warfare, intense and dangerous romantic entanglements begin to form, threading a thin, high-stakes line between passion and betrayal behind bars.