One day, Kinjiro encounters a mysterious high school boy. His true identity is Genji Kaku, his childhood friend who has rejuvenated and become the ring warrior RyuRanger! Genji's competitive spirit toward Kinjiro burns as fiercely as ever, and before they can even celebrate their reunion, they agree to a three-match showdown for the ring. Watched over by judges like Hoeru, they clash fiercely in cooking, menko, and baseball. As the rejuvenated grandpas battle in earnest, the Bridan suddenly barges in, plunging the situation into utter chaos...!