In their underground lair deep beneath the city streets, the Turtles and Master Splinter are suddenly attacked by a horde of Mouser robots! These mechanical menaces chomp through stone, steel, and even Turtles.

The Turtles discover the source of the Mouser robots that trashed their old lair: Dr. Baxter Stockman -- a noted technological genius/inventor, who tries to pass off the Mousers as a means to eradicate the city's rat problem.

When April O'Neil wakes up in the Turtle's lair she has major trouble dealing with the reality of four giant talking Turtles and a Zen-master rat, but she calms down when she hears the official ORIGIN of the Teenage Mutant Ninja Turtles!

Raphael is a little cooped up underground with only his brothers and Master Splinter. When Raphael almost clobbers Michelangelo in some brotherly sparring, it's pretty apparent that Raphael needs to get out … let off a little steam.

When a scientist accidentally unleashes a super-powered Nanotech monster with a childlike mind, it adopts a small-time grifter as its father figure, and the mayhem begins!

The Turtles, investigating a strange blackout, discover the Foot Ninja stealing a Japanese ceremonial sword from the Metropolitan Museum of Art. The sword turns out to have incredible powers -- able to create powerful vibrational shockwaves.