世界著名的機械工學者葉山博士，連同大兒子譲治、次子竜治，為最年少的三弟健治舉辦生日會時，三人就在途中被達達星人捕捉了。

　　後來達達星人派遣機械人軍團侵略地球，此時由宇宙來了兩個機械人。他們就是移植了譲治及竜治所有性格記憶的天地雙龍。此兩個等於親生兄長的機械人，就開始為地球作戰了。

Space Ironmen Kyodyne was a Japanese tokusatsu science fiction superhero television series. The show, like numerous others of its type and era, were produced as a joint effort between manga artist Shotaro Ishinomori and Toei Company producer Hirayama Tôru. It premiered in 1976 and ran for 48 episodes. The show is well known for its strange plot and costume design, rapid-fire and purposefully disorienting editing, and unique, sometimes surreal, atmosphere. The late Yūsuke Natsu and Takeshi Sasaki starred as Skyzel and Grounzel respectively.