Humanity has successfully colonized all the planets in the Solar System, with intentions to continue into new frontiers. Individuals live stable lives in these colonies, including young high school students living in 4th Tokyo on Mars. Two of these students are Iris Shirazaki and Mizuki Sera. Iris is finishing her last year of high school while studying to be a test pilot while her friend Mizuki also works as a mechanic on the aircraft. Her own brother, Kaito, oversees Mizuki and Iris as their homeroom teacher and program director.

Showtaro Morikuboas Kaito Sera (voice)
Yuma Uchidaas Nagisa Kiryu (voice)
Sora Amamiyaas Iris Shirasaki (voice)
Ari Ozawaas Mizuki Sera (voice)
Yu Kobayashias Angelina / Hanako Hattori (voice)
Minami Tsudaas Makoto Ryoke (voice)
Toshiyuki Toyonagaas Kojiro Kitahara (voice)
Aya Suzakias Tsubasa Hanaoka (voice)
Takayuki Kondoas Sakugo Maioka (voice)
Kana Asumias Yuna Nonen (voice)
Keigo Koyanagi
Yuki Hayashi