Running short of money, office lady Saki Watase is introduced to a part-time job where she's tasked with reviewing XL-size condoms. While receiving an escort home after a night of drinking, Saki's "demon" boss Keisuke Sudou notices that she's carrying a large quantity of condoms. Once Saki explains her circumstances, Keisuke reveals that he is XL-size. A romance between the two thus begins.