Hoping to earn some extra cash, office worker Saki Watase signs up for a product review program. However, when the first item sent by her new part-time job is a large box of XL condoms, Saki decides to set the task aside. Later, at a drinking party with her coworkers—including her competent but infuriating "demon boss" Keisuke Sudou—Saki gets extremely drunk, so Keisuke offers to walk her home. When they arrive at Saki's apartment, Keisuke immediately notices the substantial number of XL condoms his subordinate possesses. After she explains the circumstances of her part-time job, Keisuke offers to help with the testing—revealing that he is XL-sized!