On his birthday, Takumi discovers that he is one of the few remaining males in a world facing human extinction. To ensure the survival of the species, he is granted a "Compulsory Conception Permit," which gives him absolute authority to impregnate any woman. Tasked with the mission of mass procreation, Takumi begins utilizing the permit on the women in his life, including his sister Ena and childhood friend Rin, as he embraces his role as the world's designated "sex warrior."
Takumi is granted a series of specialized sexual licenses, including one for adult toys, leading to provocative encounters with Sara and a daring public tryst with Saki-nee on a train. After a time skip, he receives the ultimate "Pregnant Sex License," tasking him with satisfying his pregnant partners as part of a government-mandated strategy to combat population decline.