The protagonist is a demon from another world, sent to Earth on a mission to collect human souls for the dark lord who rules the demon realm. However, upon arriving on Earth, the demon becomes increasingly intrigued by human emotions and begins to question their loyalty to the dark lord. As the demon interacts with humans and experiences love, compassion, and friendship for the first time, they start to reconsider their mission and purpose. This internal conflict leads the demon to ultimately defy the dark lord, choosing to protect the very souls they were originally sent to claim.