A cafe ran by her grandfather. After news of his sudden death, the heroine gets involved with the cafe at her grandfather’s last request. At the cafe, where the atmosphere is somehow mysterious, she met a group of mysterious men. “Certainly no one you know—I’m a customer from another world.” The man who smiled cheerfully was the self-proclaimed “Demon King.” Was this meeting coincidence—or fate? And what happens when she meets these otherworldly people who aren’t quite people is…