Kotori works at a customer service center, where she spends every day apologizing to angry customers. She can't stand her coworker Kagami, who can soothe even the most unreasonable complainers with his flawless, godlike handling. With his smart work ethic and dazzling, gentle smile, he's earned the nickname "Apology Prince." Kotori vents her inferiority complex and stress toward him through solo play—her body is so tight that even one finger won't fit, yet she dreams of someday experiencing pleasurable sex. One night, after getting completely drunk, Kotori wakes up to find Kagami in front of her, doing something unspeakable. "Is it true you like me? No, more importantly, put that XL thing away!?" As Kotori reels in confusion, Kagami behaves unlike his usual self. This is a steamy office love story between a petite 148cm heroine and her XL-sized rival coworker, filled with gap moe and the transformation of a gentle prince into a possessive, obsessive lover.