Summer has arrived in Mayunan City! Mayunan High School's traditional long-distance swimming competition is to be held at Otokoran Beach, and the Defense Club and other students are in high spirits. Among them, the one most devoted to the event is Student Council President Doumeki Tamato. His passion, which has him putting aside the conquest of the Earth for the time being and betting on winning the long-distance swimming competition, seems to be somehow connected to his past with Unzen Shinkurou... And so Doumeki and Unzen clash. The key to victory lies in... Red poop? (thetvdb.com)