One day in summer vacation, two girls suddenly comes to Shintaro's house. They came to his house under Shintaro's father's command, who is a robot engineer, to test wife robots that he has invented, Luna and Sora. At first, he refuses, but later he accepts it reluctantly.... That night, Shintaro is given "the Love Meter" from Luna and Sora. When he makes love to one of them, the meter increases one point and the one who gets less points will be scrapped.... His strange life with two robots starts....