The fearsome Demon Lord Satan's plans to conquer Ente Isla are thwarted by the hero Emilia, compelling him to escape to modern-day Tokyo with his loyal general. Stranded in a world devoid of magic, Satan assumes the identity of Sadao Maou and works at a fast-food joint to survive. As he navigates mundane tasks and aims to scale the corporate hierarchy, he sets his sights on ruling Earth, offering a comical take on the challenges of everyday life for a hapless demon lord.