Shinji grew up in an orphanage after his parents died in an accident many years ago. Years later, he is contacted by a maid named Zero, who claims that Shinji’s father was a millionaire’s only son. Shinji will now be the heir to his grandfather’s firm. Shinji is apprehensive about inheriting a business from someone he doesn’t know, especially because he has plans for his own life, including marrying his childhood friend Sae. The only issue is that his grandfather will not accept no for an answer. He did, however, offer an opt-out option: if Shinji can locate a female with a specific birthmark, he will be granted his freedom and will not be forced to inherit and head the corporation. The only catch is that the birthmark won’t appear until the girl reaches her climax. How will Shinji get out of this situation while remaining true to his childhood love?