After Ren battles a DearS Biter attempting to recapture her, Takeya asserts his rights as Ren"s owner, thereby invalidating the Biter"s mission. However, this just makes things more complicated. Takeya"s life is further complicated by the arrival of his little sister Natsuki, a rapid fan of the alien DearS who immediately declares herself Ren"s bosom buddy. Of course, she doesn"t necessarily take it lightly that Ren declares herself Takeya"s slave.