"After an accidental encounter with an unknown element in the sewers of the city, the Rat King finds his ability to control the hearts and minds of rodents is waning. But in its place, he finds the ability to control reptile life, which will totally make things harder for the Heroes in a Half Shell! Plus, the TMNT are stoked when Professor McGuffin sends them on a special expedition to the ocean floor where the heroes are shell-shocked to discover...