Yuuto's been sent to another world, where he is now commander, or "Patriarch" of a clan of warriors.  To survive in this new world, he uses his cell phone, his only connection to the girl he loves back home.
In other words, Earth in the late Bronze Age.
Anders gesagt: in der späten Bronzezeit.
En otras palabras,
la Tierra en la Edad de Bronce.
En otras palabras,
la Tierra en la Edad de Bronce.
In altre parole, la Terra
alla fine dell'Età del Bronzo.
Resumindo, o planeta Terra
no fim da Idade do Bronze.
Другими словами, сейчас 
поздний Бронзовый Век.