After the Showdown, The gang are still trying to stop Shredder and also the Kraang. A new Kunoichi came back to her town to fight Shredder with the Turtles. Her name is Mai a niece of Splinters oldest friend and April's best friend. Leo doesn't trust her one bit. Even though she is good, the Shredder killed her parents. Can a certain turtle show her that revenge isn't the answer?