A cafe ran by her grandfather. After news of his sudden death, the heroine gets involved with a 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…