Ao, born as a rare Omega with only 10% Omega traits rather than a normal 100% Omega, was thought to be a Beta in the public as his slight heat would disappear during his estrus periods by taking light heat suppressants. He vowed to live his life out as it is without being bound and controlled by an Alpha, but one day, Ao experienced a lot of change in his life after he helped a crouching man on the street, who was Reiji, a freeloader Alpha...
(Source: Kadokawa, translated)