The third entry in Tadao Nagahama's Romance Super Robot Trilogy. (#1: Chou Denji Robo Combattler V, #2: Chou Denji Machine Voltes V) Following the destruction of their home world, survivors from the planet Barm travel to Earth with the intention of negotiating the purchase of land for emigration. Unfortunately, during these negotiations, the Barmian leader, Leon, is assassinated by his second-in-command, Olban, and the Earth delegation is framed for the murder. Amid the ensuing chaos, Doctor Isamu Ryuuzaki of the Earth delegation is shot and killed. Shortly after the talks end disastrously, the Barmians (referred to as "Valerians" in Starbirds) launch a campaign of terror against Earth, led by Leon's son, Admiral Richter, who deploys various "Mecha Soldiers" against the planet's defenses. The only barrier between the Earthlings and annihilation is Daimos, a transforming super robot that utilizes karate, and its pilot, Kazuya Ryuuzaki. However, this changes when he meets and falls in love with a mysterious girl named Erika, who turns out to be Richter's sister. As they struggle to reunite, Kazuya and Erika each discover that the other's people are not entirely evil... and that their own people are not entirely good.