Teenage Mutant Ninja Turtles (2003): Season 1, Episode 2

1 - 2: A Better Mousetrap

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. Donatello gets one of the broken Mousers working and the Turtles chase it through the sewers. Meanwhile, Stockman's lab assistant April O'Neil uncovers a secret subterranean facility where hundreds of Mousers are being manufactured and stored - but to what end?