Cruising through space in Astrotrain, a group of Decepticons discover an unknown planet with the Autobot symbol emblazoned across the surface. Surprised that the planet is completely abandoned, they find a strange obelisk-like stone. They activate it, generating a holographic warning. Ignoring the admonition, they move on to a building and find a huge device which turns out to be an extremely powerful heat ray. As they leave with it, a meteorite gets caught in Astrotrain's jetstream, but his passengers quickly destroy it with their new weapon. Unfortunately, several fragments of it hit and damage Astrotrain and a piece also injures Megatron. Later, on Earth, Megatron begins to rust, and the panic-stricken leader orders the immediate capture of Perceptor. As this happens, Perceptor is being awarded a coveted scientific award for the creation of an anti-corrosive compound called Corrostop, with which the Statue of Liberty is covered. However, as he grants an interview on his triumph, Perceptor is abducted by the Stunticons. Unable to resist the scientific mystery, Perceptor examines Megatron and identifies the spores as cosmic rust, also discovering that the disease is aggravated by the heat ray. He agrees to help Megatron in return for the destruction of the heat ray, little suspecting that Megatron's consent is, as always, void. Megatron lets the Autobots retrieve Perceptor, causing them to contract cosmic rust from him. Even Teletraan 1 is infected, but not before revealing that cosmic rust first appeared on a planet called Antilla--the planet discovered by Megatron's group--and killed its entire population. To survive, the Autobots must create more Corrostop, but as a mysterious ingredient is no longer to be found, they travel to the Statue of Liberty to get a sample for duplication. The Decepticons try to destroy the statue, but the furious battle sees Superion defeat Menasor and destroy the heat ray, sending the Decepticons on the retreat as cosmic rust is expunged from Earth.