Nao Takanashi was adopted into the Takanashi family, and the day she found that out turned her feelings for her older brother Shuusuke into a campaign she runs with eroge, staged accidents and no shame whatsoever. Shuusuke spends his days deflecting her while his childhood friend Iroha Tsuchiura announces herself as his girlfriend and class president Mayuka Kondou makes him her personal servant. The Takanashi house fills up with girls, each one certain of her claim on him.