The Bessho family patriarch goes away for a while owing to a job assignment, leaving siblings Yoshihiko and Koyoi alone in the house, much to Koyoi's delight, so as to keep her brother to herself at home. Meanwhile, Yuuji Arihara, upset about a misunderstanding about his sister Ayumi and Misao, forces a lollipop into Misaki Yamamoto's mouth to explain his point to Yoshihiko. Yoshihiko, embarrassed at what his friend had just done, and holding a secret one-sided love for Misaki, apologizes and leads Yuuji away. Upon receiving a call from Misaki, Yoshihiko meets her at a local restaurant. Koyoi, alarmed at the fact that her brother likes someone other than her, trails him in order to "scout the enemy." Misaki reveals her feelings for Yuuji and asks Yoshihiko for help. Being the nice guy that gets looked over, Yoshihiko agrees to help.
兄の良彦のことが大好きな別所小宵。だが良彦は同級生の山本岬に恋焦がれていた。父が出張で不在のある日、今宵はチャンスとばかりに(!?)、兄に新婚夫婦のように接しようとする。そんなところに、岬から良彦を呼び出す電話が掛かってくる。「お兄ちゃんにカノジョ!?」小宵は浮かれて出掛ける良彦を尾行し始めて…。
El patriarca de la familia Bessho desaparece por un tiempo debido a una asignación de trabajo, dejando a los hermanos y Yoshihiko Koyoi sola en la casa, para el deleite de Koyoi, con el fin de mantener a su hermano a sí misma en casa. Mientras tanto, Yuuji Arihara, molesto por un malentendido acerca de su hermana Ayumi y Misao, obliga a una piruleta en la boca de Misaki Yamamoto para explicar su punto de Yoshihiko.
