1) Dendou Ouji-sama Takahashi
Koto is a high school girl who accidentally bought Takahashi, 'the perfect boyfriend' who's actually an android. He's handsome, charming, devoted, and kind, but the one Koto actually likes is a boy in her class, Ishida, who she always fights with. She decides to try out Takahashi because she thinks Ishida will never see her romantically, but...
2) Dendou Ouji-sama Takahashi 2go 3go
This story is a kind of prequel to the original story, Dendou Oujisama Takahashi and is about two other androids in the "Takahashi" series.