Earth is invaded by an interstellar terrorist group, Big Fire (the Gargoyle Gang in the American version), led by Emperor Guillotine.

They flee onto an elevator leading to a complex where a Pharaoh-like giant robot is being built by captive scientist Lucius Guardian, who gives Daisaku and Jūrō its control device.

He wears a long robe, carries a staff with a white orb at one end and can grow to a great height, which he does only in the final episode of the series.

[1] A hastily edited seven-minute highlight reel of Voyage Into Space was created for the Super 8 home movie market during the early 1970s by Ken Films.

Gunfights are a staple of each episode and the show's two child leads (Johnny Sokko and Mari Hanson) were frequently seen shooting with the other Unicorn agents.

In one episode, Johnny and Mari are captured and tied to trees by Gargoyle and are within seconds of being executed by a firing squad when they are rescued by Unicorn agents.

(At least one US TV station, WXON in Detroit, ran disclaimers before each show saying, "Remember, kids, Johnny Sokko is make-believe and the actors are just pretending.")

Beckoned by forces he cannot understand, Daisaku is made to bond, body and spirit, with the ancient weapon and defend his homeland from the incoming evil.