The twins, Oona and Hooru, come to the house of Takeuchi Kou, a super-skilled porn star. They appear to be just normal girls but they're actually not. In fact, they are succubi who devour humans' sexual desire. The reason they come to Takeuchi's house is to be with their beloved Takeuchi Kou. However, a succubus can't fall in love with a human because of the species barrier. In order to make this possible, there was a way for a succubus to become a human. That is... To collect abstinence balls that can be obtained through abstinence. In order to get the abstinence balls, they pull each other's legs, make each other come, and interfere with each other, and the abstinence survival battle begins.