With the hopes of making a bit of extra cash, office worker Saki Watase registers for a product review program. But when the first product her new part-time job sends her is a huge box of XL condoms, Saki decides to put the task to the side.

Later on, while at a drinking party with her coworkers—including her competent but infuriating “demon boss” Keisuke Sudou—Saki ends up drunk out of her mind, so Keisuke offers to escort her home. Upon their arrival at Saki’s apartment, however, Keisuke immediately takes notice of his subordinate’s substantial number of XL condoms. When she explains the circumstances of her part-time job, Keisuke offers to help out with the testing—revealing himself to be XL-sized!