A mysterious young man, who has been tracking the Turtles' movements, wishes to train under Master Splinter's guidance. Meanwhile, the Turtles race to stop Lord Dregg's plans for global domination.

Dregg hires an alien bounty hunter named Medusa to help capture the Turtles. The Turtles must fight off this new threat. Meanwhile, Carter realises that he is more of a hindrance than a help. Meanwhile, an alien slug, called a Slorr, hatches & begins terrorising the city.