11-year-old Yusuke and his classmates camp in the woods and see a strange light. They discover a small metallic object like a robot which talks, calls himself Tetra and knows Yusuke's name. Tetra can create wonderful gadgets but actually has to save the world with Yusuke's help from extraterrestrials with bad intentions.
Soichiro Kanzaki
Noriko Kinoshita
Misaki Kinoshita
Yusuke Sakamoto
Hidetaka Ono
Toshiya Matsuoka
Yusuke's Father
Yusuke's Mother
Misawa
Female Researcher / Voice of Tetra
Snack Shop Lady
Man
Agent B
Misaki Kinoshita, 20 years later
Byoid (voice)
Agent A
Yusuke Sakamoto, 20 years later
Toshiya Matsuoka, 20 years later
Hidetaka Ono, 20 years later
