Four turtles fall into the sewers and are befriended by Hamato Yoshi a Japanese man sent to New York who was forced to live in the sewers. One day he sees a strange green glow which transforms the four turtles into human-like creatures. Hamato (now Master Splinter) changes into a giant rat from the green glow and teaches the turtles the skills of the ninja as they team up with news reporter April O'Neil to battle against Yoshi's arch enemy Shredder and Krang, an alien warlord from Dimension X.

Leonardo, Raphael, Michaelangelo and Donatello must save New York City from the evil crime lord Shredder and his assistant, Baxter Stockman. The Turtles must fight foot soldiers, mice, and gangs and get help from their sensei Splinter, her friend April O'Neil, and her partner Casey Jones in an action-packed new series.

The Teenage Mutant Ninja Turtles are back in an all-new animated series on Nickelodeon! Surfacing topside for the first time on their fifteenth birthday, the titular turtles, Leonardo, Michelangelo, Raphael and Donatello, find that life out of the sewers isn't exactly what they thought it would be. Now the turtles must work together as a team to take on new enemies that arise to take over New York City.

The Turtles — Leo, Raph, Donnie and Mikey — each will go it alone for the first time. Faced with new threats and teaming up with old allies, the Turtles will discover who they really are when they don’t have their brothers at their sides.