After having to repeat his final year in Tsurugamine High School, Kotaro is drawn to Judo through the encounters he make with first-year students Kumi Mifune, Sanshiro Saigo and Daigo Daigo. Having lost to Kotaro, first-year Judoka Kumi Mifune endured to learn the Karate discipline in order to defeat Kotaro. However, the ambitious delinquent Judoka Daigo captured her as a bait to take on Kotaro and take over his long-standing Kyokutan dojo. Sanshiro Saigo was taken as well and caused the Judo Club to be involved in the conflict with Kotaro.
With the return of many previous characters mixed with the appearance of new characters, this new arc brings Kotaro and Mayumi to the world of Judo filled with the familiar mix of comedy, ecchi, and martial arts.