Spectrum was established to protect the Earth from the Mysterons, an alien race from the planet Mars who attacked Earth after an exploratory mission was mistaken for an invasion party.

Its chief operatives (named after the colors of the spectrum) were:

• Colonel White (Born In England)
• Captain Scarlet (Born in England in 2036)
• Captain Grey (Born in Chicago)
• Captain Ochre (Born In America)
• Captain Blue (Born in Boston)
• Captain Magenta (Born in Ireland)
• Lieutenant Green (Born in Trinidad)

Colonel White at Spectrum Command Console

Spectrum's defenses supported Cloudbase, a the flight base for a fighter squadron of female pilots called "The Angels" (including Symphony Angel, Melody Angel, Rhapsody Angel and Harmony Angel).

Captain Gray, the commander of the submarine Stingray and Lieutenant Green were members of the World Aquanaut Security Patrol who assisted Spectrum in its battle against the Mysterons.

Theme Song Lyrics

Captain Scarlet,
He's the one who knows the Mysteron Game,
And things that they plan.

Captain Scarlet,
To his Martian foes a dangerous name,
A superman.

They crash him, and his body may burn,
They smash him. But they know he'll return,
To live again.

Captain Scarlet,
As the Angels are flying wing to wing,
Into the scene, Spectrum Is Green.

Captain Scarlet,
Though the Mysteron's plan to conquer the earth,
This indestructible man will show what he's worth.
Captain Scarlet