Leo takes the Turtles to train in the woods in an advanced ninja ritual; the Turtles must overcome their weaknesses and face their enemies to become a true ninja.

When the Turtles return to the city to search for Splinter, they discover that the city has been overrun with Kraang.

Karai searches for the legendary Kuro Kabuto, claiming to be the rightful heiress of the Foot Clan, when she suddenly encounters an old rival.