Keita has two older step-sisters, Ako and Riko, but since they aren't related by blood, they love him in a lustful way. After a mishap at school, Ako and Riko finally confess their love to him. Keita dislikes the thought of seeing them other then brother and sister, but as he tries to enter the same school as his sisters, he slowly becomes attracted to them.
The series was good all the way through. I enjoyed watching it, and looked forward to watching every episode.
A tad more T&A than i expected. But the series remained cute, and fun to watch.