Seina Yamada has been waiting so long to return to his home, Earth.
But so much has changed; his sister is engaged to Kiriko's brother Kai,
and his parents' old store is now a huge mall.
Furthermore, he is to stay at Kiriko's mother's house...
At present, Earth is a planet 
with an early stage civilization,
في الوقت الحاضر، الأرض هي كوكب
،بحضارة في مراحلها الأوّليّة
Derzeit ist die Erde ein Planet
niedriger Zivilisationsstufe,
La Terre
est encore une planète primitive,
Al momento, la Terra è un pianeta 
con una civiltà in fase iniziale,
No presente, a Terra é um planeta
em estágio inicial de civilização,
Она сейчас на раннем этапе цивилизации.