Matthew, a gang leader once Hudson’s bodyguard, kidnaps the fallen aristocrat Hudson out of inferiority and obsessive love, locking him in a penthouse with a golden tracking ankle chain. Everyone believes Hudson is a helpless victim, except Matthew’s sharp subordinate Elena, who senses his unnatural docility. The truth reverses everything. Hudson adores Matthew, who once nearly lost his hand protecting him. To escape an arranged political marriage and save Matthew, he sabotages his family’s mafia empire and secretly funds Matthew’s rise. He pretends to be captured on purpose, manipulating Matthew’s possessiveness. After Elena uncovers all evidence, the pair confront each other. They reconcile, eliminate all rivals side by side, and co-rule the underworld, willingly becoming each other’s eternal cage.