The Planet Arus has been under attack by the ruthless King Zarkon for many years. Responding to a call for help, Galaxy Garrison sends a team of five young space explorers, Keith, Lance, Sven, Hunk and Pidge, hoping they could reach the devastated planet, in hopes to offer help.

However, they are captured by Yurak before they could land on the beautiful planet. Knowing that they would be used as entertainment for the citizens of Doom in Haggar's Robeast arena, they work out an escape plan, to find a way out of the Doom Castle and a way to get back to Arus. Hunk's brute strength and Pidge's agility, they are able to break out of their meager cell and hijack a Doom Slave ship.

Pursued by Doom Robot fighters, the five explorers managed to reach Planet Arus. They then recall a legend of a mighty robot, named Voltron that once stood and fought against the forces of Doom. Though defeated, whe King Zarkon's witch, Haggar disguised herself as a beautiful goddess, then split the giant defender into five lion ships, sending the robot lions crashing to Arus' surface.

The five explorers then vow to find a way of learning the secret to Voltron, in hopes to resurrect the mighty robot, and save Arus from the forces of King Zarkon.