Spurred on by his fantasies of Richika-sensei's reward should he pass his supplementary exams, Shuusuke is doing his best to follow the tutor's rigorous learning method. However, said method involves restricting Shuusuke's lusty appetites, which soon turns him into a ticking time-bomb of repressed sexual tension.
Desperate to keep her oniichan sane, Nao tries to conceive of ways to give Shuusuke that climax he so frantically needs. But like grandmasters waging war on a chess board, Richika-sensei deftly places each of Nao's pieces in check. Your move, Nao.