An isolated island at the far edge of the Empire, designated as a prison for criminals. Strangely, it also serves as a decadent retreat for the nobility, where they indulge in their vices while convicts are forced to cater to their whims in exchange for reduced sentences. The island was once home to an ancient, mysterious dungeon that has long been sealed for safety. Yet rumors persist that the dungeon is stirring once more, its secrets threatening to resurface. The Holy Knight Liana is sent to investigate these claims, expecting a straightforward mission. However, her arrival takes an unexpected turn. Stripped of her knightly identification the moment she lands, Liana is accused of being an intruder, arrested, and forced into servitude in the island’s brutal Coliseum. Now trapped in this perilous place, Liana faces a daunting challenge: can she complete her mission, reclaim her freedom, and escape the infamous Prison Island? Or will she succumb to its dark temptations, losing both her purity and her sacred powers, doomed to remain a prisoner forever?​