The Big Guy and Rusty face off against the Legion Ex Machina's evil creation: A.R.G. -12, a.k.a. Argo. When a Nucleo-Protonic blast from Argo triggers a malfunction in Rusty's power core, the boy robot fears that he will be disassembled due to the fact that he is going out of control.

A telepathy experiment goes awry and a Quark Scientist, Dr. Neugog, is transformed into a giant brain on spidery legs. Neugog uses his telepathic powers to drain the minds of the world's greatest scientists. Meanwhile, Dr. Slate accidentally discovers that there's a man in the Big Guy suit.

Big Guy and Rusty find the Legion's headquarters and rescue the creator of the Big Guy armor, who Rusty refers to as Big Guy's dad.

The Legion Ex Machina creates a Big Guy duplicate.

Jellyfish create duplicates of the crew of the new Quark research centre at the ocean floor.

Pierre becomes a brain-sucking monster when he plays around with Dr. Neugog's telepathy helmet. Quark uses the fiendish Neugog to track him down.

Dr. Slate, Big Guy and Rusty find out that the Legion Ex Machina's mysterious ""final assembly"" is taking place in a network of underground tunnels. When Big Guy and Rusty find the tunnels, they derail a robotic train. Inside the massive train's cargo hold is a gigantic hand that boasts a built-in high-tech cannon. With their plan uncovered, the Legion Ex Machina members decide to activate their latest creation ahead of schedule and missing a hand.

The Big Guy is decommissioned in favor of Quark Industries' newest creation, Rusty the Boy Robot. But when an alien Annihilator threatens to destroy New Tronic City, it's clear that Rusty is not quite ready for prime time.

Giant jungle animals wreak terror in the Congo.

Donovan unveils Quark's latest prototype: tiny liquid metal robots called Nurds that repair and upgrade any technology they come in contact with. When Big Guy becomes infested by the Nurds, they repair its original artificial intelligence circuitry, making Big Guy a fully functioning robot, which removes Dwayne from the pilot's seat. But shortly after the new Big Guy successfully completes his first mission, things go awry.

On Quark Industries' recently christened space station, the computer, known as Edie, has gone mad. Threatening to destroy the moon, Edie demands delivery of the Ubik Chip, which would allow Edie to gain control of all computers on Earth.

Big Guy and Rusty go back in time to the civil war.

A virus-carrying alien threatens the world, and Dr. Slate must take the helm of Big Guy.

Rusty tags along with Dwayne to his nephew's birthday party. Rusty's present is a piece of stolen alien technology, known as a Dimetrium Agglomerator. The aliens, Emek and Naard, own the Agglomerator and come to claim it.