Frip the Polarisoid arrives back on Earth with his family for a visit, and must ultimately ask the Turtles for help in reclaiming his camera while helping them stop Krang's latest plan to conquer the city.

Tired of fixing everything in the lair, Donatello decides to clone himself so he can work on his other inventions. However, Donatello's clone turns against him and joins the Rat King in an attempt to conquer the city with a rat infestation.