An omega must be petite, cute, and dainty—yet Lee Doyun has anything but these features. As the fourth son of an alpha man and an omega woman, Doyun inherited his mother's secondary sex characteristics. However, he is tall and muscular, he cannot emit pheromones, and he has never gone in heat. Despite his unusual condition, Doyun is not a bit bothered by it and even prefers that his body stays this way. One day, Doyun suddenly experiences his first heat and is prescribed medication by his doctor to control his pheromone imbalance. Although mildly annoyed, Doyun must follow his doctor's orders to avoid causing trouble at his workplace, as everyone assumes he is an alpha. But due to a slip-up, Jung Taehan—Doyun's rival co-worker and an alpha—finds out that Doyun is an omega, and later, they spend a night together. With Doyun's body now being aroused every time Taehan gets close and Taehan feeling unable to leave Doyun on his own accord, their relationship evolves from butting heads into something much more intimate. [Written by MAL Rewrite]