Ayumu Aikawa must continue to fight the Megalo in place of Haruna, who continues to recharge her magical powers. While trying to figure out the mysteries behind the people who are releasing these Megalo in the world, Ayumu meets a beautiful, black-haired girl by chance, and she only has eyes... For his butt.
A chibi robot doll appears in the room of a typical high school boy. The robot claims the boy as her husband and then a beautiful girl comes out of the doll's mouth who knows the boy from 10 years prior and had been promised his hand in marriage.
The story begins with Izumi Hayato running to be student council president. But when a beautiful girl swings in promising the liberalization of love while flinging condoms into the audience, he ends up losing to her and becoming the vice president. At the student council meeting, the newly-elected president invites herself over to Izumi's house, where she promptly announces she is to become Izumi's wife thanks to an agreement—facilitated by alcohol—made between their parents when they were only 3.