Yuki and Haru, a father and son duo, are not biologically related. Yuki, an omega, still leads a peaceful life with his alpha son Haru as he doesn't suffer from heats. Haru, who turned 18 years old, confessed his feelings to Yuki through a kiss. This intimate moment caused a transformation in Haru's body as he experienced his first heat, and the temptation of Yuki's pheromones was too hard to resist.