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.
If we're going to make an oath
with the Horn Clan,
Wenn wir einen Eid
mit dem Horn-Clan eingehen,
Si vamos a hacer
un juramento con el Cuerno,
Si vamos a hacer
un juramento con el Cuerno,
Si on fait un serment
avec les Cornes,
Se il Clan del Corno giurerà fedeltà,
Se iremos firmar promessa
com o Clã dos Chifres,
Если Клан Рога даст нам свою клятву,