Kyle was reincarnated into a fantasy world and eventually recruited into the hero’s party, a group assembled to defeat the newly revived Demon King. Over time he has formed deep bonds with his companions: Noelle the high priestess, Dal the thief, Tiger the beastfolk warrior, Sasha the mage, and Eclair the hero. Their expedition proceeds smoothly until a goddess appears before Kyle and reveals a stunning truth: one of his five trusted friends is actually the Demon King in disguise. Tasked with uncovering the impostor, Kyle is uniquely suited for the mission because he possesses a special cheat ability that prevents the Demon King from reading his mind. He must now investigate his own party members without arousing suspicion, all while maintaining the group’s cohesion and continuing their quest. The story unfolds as Kyle systematically suspects each friend in turn, gathering clues and confronting the possibility that any one of them could be his greatest enemy. The narrative balances fantasy adventure with a tense whodunit, exploring themes of trust, deception, and the blurred line between ally and foe.