Leonardo, tired of Raphael’s constant criticism, lets his brother try his hand at leadership for a while. Meanwhile, Leonardo meets a beautiful and dangerous female ninja who tries to lure Leonardo to the dark side.

The Turtles must face off against a new enemy, The Rat King, who threatens not only to take control of the city, but Splinter’s mind as well.

The Turtles get their first taste of high school when April’s school project draws Kraang attention.