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.
Im pretty liberal as a chick and still get kicks out of the echi/fanservice stuff, but the story is weak, and drool during the tongue kissing and wet panty shots are a little over the top. Seems this is more for guys home alone on a Friday night than real entertainment.