Mizuhara Reito is an ordinary boy who wakes up in a world of 5 billion women and 5 men. Now it's up to him to repopulate the human species. Can he stay loyal to his missing childhood friend when all humankind is counting on him to sleep with as many girls as possible?
If we don't do something, humanity 
will actually be destroyed.
Wenn Sie nicht einschreiten,
Si no hacemos nada,
la humanidad se extinguirá.
Si no hacemos nada,
la humanidad se extinguirá.
Si nous n’agissons pas,
l’humanité court vraiment à sa perte !
Dobbiamo fare qualcosa, o l'umanità
finirà davvero per estinguersi!
Se não fizermos algo, a humanidade
será realmente destruída.
Ведь если ничего не сделать,
человечество сгинет.