Himawari, the younger sister, was plotting to take her older brother Hiroyoshi's virginity. Hiroyoshi, who has no luck with women, was also conscious of Himawari. Himawari persistently seduces Hiroyoshi without a bra, and Hiroyoshi, unable to resist, tries to touch her budding breasts while she is sleeping. However, it was a trap set by Himawari! The next day, Himawari blames him for this, and instead of forgiving him, she makes Hiroyoshi wear an eye mask and zips up his pants...