Fathers & Sons - S5.E9

Weary after their first battle with the new Shredder, the Turtles doubt they can defeat him. To lift their spirits, Splinter and the Ancient One shares a tale of the Turtles’ toddler days. The story reveals that though the Turtles were small, they overcame impossible odds to defeat a phantom bent on reviving the Shredder, though they may not remember it.