Keita has two step-sisters(KissXSis) who love him in a lustful way and have no problems expressing it, even going so far as to have daily, public competitions for his affections. Because of their obvious feelings, Keita is mocked by his friends, to the point where one day he gets fed up and explodes at them in school. However, this has an unexpected effect: the pair confess their feelings for him in front of everyone and leave. Feeling sorry about hurting their feelings(KissXSis), he chases after them and promises that he'll study hard in order to get in the same high school as them. KissXSis is the single best fanservice show I've ever seen in mangahere, and I'm not sure exactly why, but in terms of pure,it draws me in more than anything else of its kind. The first half reminded me a bit of KissxSis with the girls going after the fake 'penis' like that.