The Turtles begin training with the mysterious Ninja Tribunal, experimenting with new powers and weapons. After securing the first of the Tribunal's Lost Artifacts, our heroes learn to their horror that the "great evil" they are destined to face is the long-imprisoned spirit of the one, true Shredder!

The Turtles and company continue their training under the Ninja Tribunal, learning to fight in the physical as well as mental and spiritual worlds. They're going to need that knowledge, because the second artefact of the Shredder has been found, guarded by a horde of nasty Tengu demons that eat Acolytes for breakfast… literally!