Yuu Shiratori was living a happy life, secretly filming his beautiful and cute sisters and using them as wank material. But that routine comes to an end when two lewd sisters suddenly show up at his house... The moment they met, the younger sister, Tsugumi, tied him up and made him cum with a dry hump, and the older sister, Narumi, teased him, saying they wanted to feel good together... In the end, perhaps influenced by this, even his kind and gentle older and younger sisters suddenly start coming on to him with a change of heart!! And so begins his naughty new life with four extremely lewd sisters!!