Makoto is an office lady who has been living an ordinary life as a β. One day, he ends up living with his girlfriend's brother-in-law, Yuki, who has moved to Tokyo!? They were originally step-sisters and brother-in-law, and they hadn't seen each other since their parents divorced a few years ago. The two enjoy a fleeting relationship as sister and brother.'' But...for some reason, my chest is aching. When I'm with the snow, my body gets hot and flushed... I looked at the snow feeling like an omega and was told, It's probably my fault that you're in heat right now.'' Even though I'm a β? Yuki suddenly kisses Makoto, who is confused. He entwines his tongue with her many times, exposing his instincts as he embraces her, and a sweet numbness takes over... He looked at Makoto with love and heart and let out a sigh. My body reacts sensitively to his gentle fingertips touching my chest and pussy. "Please, I don't want to hold back anymore. I'm with my sister..." This shouldn't happen... In the step-sister-brother Omegaverse, where fate and love are intertwined.