Takumi is an average guy with a not so average set of women around him trying to live his life. This would include being childhood friends with a pair of close sisters in the house next door; Mitsuki and Satsuki. One day however he finds out that his father plans to remarry. Two girls around his age, Saori and Yui, move into his house as part of the future family to be. Takumi's choices lead to a series of very naughty events that may or may not lead to his own happiness.