While her husband is away on a long business trip, Ayane works as an assistant and maid at the home of her cousin Yu, a popular female writer with a serial in a weekly magazine. Ayane has admired Yuu, who is beautiful, kind, and full of talent, since she was a child, and feels happy living under the same roof as Yuu. However, Yuu, whom she adores like a real sister, has another side that Ayane does not know. On a quiet night, Ayane, covered in sweat and sleeping soundly under a mosquito net, unaware of anything, learns Yu's true nature.