Jiiiii～

Tall Kaori and short Sota are siblings by marriage. One day, commanded by Kaori, Sota becomes the dorm manager and coach for her university women's volleyball team. Among the members is Ayano, his first love, and they have an unexpected reunion! Sota begins living together with the club members as the dorm manager. But that night, he witnesses an unexpected side of Ayano, whom he's always admired...?!

Kaori, who had suggested the date herself, becomes flustered upon learning that Sota and Ayano went to a hotel. Still, as Sota's sister, she tries to mediate between them... Meanwhile, Sakura, Kyoka, and Yuria, having heard the whole story, come up with a bizarre theory: Since they're also members of the girls' volleyball club like Ayano, they should have the right to do the same thing! And so, they begin seducing Sota!

Everyone is present at the girls' dormitory, now with the club president, Sanae, who had been absent for a while due to family circumstances, returning to the volleyball club. Sanae, a libero specializing in defense, is petite despite being on the volleyball team, and Sota finds himself drawn to her, who is shorter than him. The group decides to hold a Genghis Khan party to celebrate Sanae's return and Sota's appointment as coach. But that night, an unexpected hint of romance awaited Sota!