As an ordinary but hard-working undergraduate, Wonhyuk diligently prepared for his overseas studies, without ever reaching out to his stepmother for help. Suddenly, appearing in front of Wonhyuk is his stepbrother, Hanseo. Within the walls of Wonhyuk's empty home, as if he’s ready to leave at any moment, the mysterious chemistry between the two overflows. "My rut is here. This time too, get through it with me." For a Beta like Wonhyuk, the way an Alpha like Hanseo treats him makes him slightly anxious... How will Wonhyuk continue to face Hanseo, a person he finds hard to understand, both in the past and the present?