Two musicians working for Umbra use their music to summon a Magnetic Monster on Earth. The Orbots must unite to stop it before it destroys the planet.

Ohno begins to doubt her worth because she's ""just an Orbot."" Shadow agent Plasmus turns her into a human at her request, but when Mighty Orbots is needed on a rescue mission, Ohno finds she can't change back and as a result, can't activate Mighty Orbots!

Deciding that Mighty Orbots is too powerful for his agents to defeat, Umbra has his agent Metanllis, who has the power to control minds, lure them to the planet Evilon with a stolen defense satellite. There, its prehistoric monsters will surely destroy the robot heroes. Meanwhile, a giant meteor is flying toward Earth, which will be devastated with both the defense satellite and Mighty Orbots unable to stop it!

Umbra creates Tobor, a giant robot that looks like Mighty Orbots, and has it run amok. Soon the Orbots are sentenced to Devil's Asteroid, the Alcatraz of space, for Tobor's crimes.

Rondu and Dia leave for a summit meeting onboard the Stellar Queen, which is taken over by space pirates. Mighty Orbots speeds to the rescue, but the pirates of misused the Stellar Queen's anti matter engine, and soon it'll explode and wipe out the entire sector!

Bo finds what she thinks is a giant jewel on the planet Targon. But when they bring it back to earth, a giant dragon-like monster hatches from it.

Shadow scientist Werag invents a weapon that destroy an entire solar system and gives the Galactic Patrol a short time surrender. Meanwhile, fearing that they're about to be replaced, the Orbots decide to prove their worth by teleporting to the Shadow Star and saving the world, but find it more heavily guarded than they thought. Rob follows, but is captured. Can Shadow be stopped in time?