On their 15th birthday, brothers Leonardo, Raphael, Donatello, and Michelangelo go up to the surface for the very first time. They witness Okumura Nari, April O'Neil, and Kirby O'Neil being kidnapped by alien robots called the Kraang. They save the girls, but now must find a way to save Mr. O'Neil. However, their presence brings the Foot Clan and their leader, the Shredder, to New York, where Nari's past comes back to haunt her.
Darkness has settled over New York City as Shredder and his evil Foot Clan have an iron grip on everything from the police to the politicians. The future is grim until four unlikely outcast brothers and a human rise from the sewers and discover their destiny as Teenage Mutant Ninja Turtles and Ronin, a masked vigilante. The Turtles and the human must work with fearless reporter April O'Neil and her cameraman Vern Fenwick to save the city and unravel Shredder's diabolical plan.