距地球500光年，一顆猶如藍寶石般星球伊柔星(Erra)，有一對兄妹歐彼(Orbit)與特菈(Terra)，以及一個陪伴機器人-歐寶(Orball)，因為一個意外他們來到地球，在此發生許多有趣的故事。

500 light-years from Earth lies a sapphire-like planet called Erra.
There, a sibling duo—Orbit and Terra—live with their trusty companion robot, Orball.
One day, an unexpected accident brings them all to Earth, where a series of fun and exciting adventures begins...