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?
Bro, Takagi-sensei... 
Everyone but Mahiru is gone.
Mein Bruder, … Doktor Takagi …
Alle außer Mahiru sind verschwunden.
Mi hermano, el señor Takagi…
Desaparecieron todos menos Mahiru.
Mi hermano, el señor Takagi…
Han desaparecido todos menos Mahiru.
Mis à part mon frère,
le Dr Takagi
Mio fratello, il dottor Takagi...
Se ne sono andati via tutti, eccetto Mahiru.
Meu irmão, o Takagi-sensei...
Tirando a Mahiru, todos se foram.
Мой брат, доктор Такаги...
Не осталось никого, кроме Махиру.