Brain is the world's greatest computer, and also the most intelligent being on planet Earth. One day, Brain decides to abandon its terrestrial moorings, and it's up to The Defenders to track it down. Unfortunately, Brain has developed an amazing army of deadly giant robots, including one with a huge "17" emblazoned on its chest-plate, with which it plans to subjugate its creators. A young boy whose family was killed by Brain's followers manages to activate Daitetsujin 17, which thereafter comes to his rescue whenever he is in danger from Brain's minions.
| Actor | Role |
|---|---|
| MMasahiro KamiyaStevie | Stevie |
| UUlf OtsukiProfessor Hassler | Professor Hassler |
 Tadao NakamaruDr. Sahara | Dr. Sahara |
 Midori TakeiJudy Sahara | Judy Sahara |
| GGō HaraguchiCaptain Bob Kendall, "The Razor" | Captain Bob Kendall, "The Razor" |
 Akihiko HirataCaptain Roper | Captain Roper |
| TTakehisa YamaguchiChief Kidd | Chief Kidd |
| LLucia SantoPink Jaguar | Pink Jaguar |
| MMio OtaBlue Jaguar | Blue Jaguar |
| KKenji TamiyaDefenders Captain | Defenders Captain |
| KKaho ShimadaCarrie Sahara | Carrie Sahara |
| MMasahiro TakashinaFred, Stevie's friend | Fred, Stevie's friend |
 Osman YusufPrisoner | Prisoner |