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?
He won't do anything reckless 
like he did yesterday.
und wird nicht noch einmal
so unüberlegt handeln.
No volverá a cometer
ninguna imprudencia.
No volverá a cometer
ninguna imprudencia.
Il n’agira plus sans réfléchir.
Non farà più azioni avventate come quella di ieri.
Ele não fará nada imprudente
como fez ontem.