S03E21: Attack of the Mega Shredder!
Leonardo decides to sneak into Shredder's lair alone, and winds up facing the biggest mutant threat yet.
Previous Episode 
Season 1
Rise of the Turtles (1)
S1E1 / 28 Sep 2012
Rise of the Turtles (2)
S1E2 / 29 Sep 2012
Turtle Temper
S1E3 / 06 Oct 2012
New Friend, Old Enemy
S1E4 / 13 Oct 2012
I Think His Name Is Baxter Stockman
S1E5 / 20 Oct 2012
Metalhead
S1E6 / 27 Oct 2012
Monkey Brains
S1E7 / 03 Nov 2012
Never Say Xever
S1E8 / 10 Nov 2012
The Gauntlet
S1E9 / 17 Nov 2012
Panic in the Sewers
S1E10 / 24 Nov 2012
Mousers Attack!
S1E11 / 08 Dec 2012
It Came From the Depths
S1E12 / 15 Dec 2012
I, Monster
S1E13 / 25 Jan 2013
New Girl in Town
S1E14 / 01 Feb 2013
The Alien Agenda
S1E15 / 08 Feb 2013
The Pulverizer
S1E16 / 15 Feb 2013
TCRI
S1E17 / 01 Mar 2013
Cockroach Terminator
S1E18 / 15 Mar 2013
Baxter's Gambit
S1E19 / 05 Apr 2013
Enemy of My Enemy
S1E20 / 12 Apr 2013
Karai's Vendetta
S1E21 / 27 Apr 2013
The Pulverizer Returns!
S1E22 / 11 May 2013
Parasitica
S1E23 / 20 Jul 2013
Operation: Break Out
S1E24 / 27 Jul 2013
Showdown (1)
S1E25 / 08 Aug 2013
Showdown (2)
S1E26 / 08 Aug 2013
Season 2
The Mutation Situation
S2E1 / 12 Oct 2013
Invasion of the Squirrelanoids
S2E2 / 19 Oct 2013
Follow the Leader
S2E3 / 02 Nov 2013
Mutagen Man Unleashed
S2E4 / 09 Nov 2013
Mikey Gets Shellacne
S2E5 / 16 Nov 2013
Target: April O'Neil
S2E6 / 23 Nov 2013
Slash and Destroy
S2E7 / 30 Nov 2013
The Good, The Bad, and Casey Jones
S2E8 / 02 Feb 2014
The Kraang Conspiracy
S2E9 / 09 Feb 2014
Fungus Humungous
S2E10 / 16 Feb 2014
Metalhead Rewired
S2E11 / 23 Feb 2014
Of Rats and Men
S2E12 / 02 Mar 2014
The Manhattan Project (1)
S2E13 / 14 Mar 2014
The Manhattan Project (2)
S2E14 / 14 Mar 2014
Mazes & Mutants
S2E15 / 27 Apr 2014
The Lonely Mutation of Baxter Stockman
S2E16 / 04 May 2014
Newtralized!
S2E17 / 11 May 2014
Pizza Face
S2E18 / 18 May 2014
The Wrath of Tiger Claw
S2E19 / 08 Jun 2014
The Legend of the Kuro Kabuto
S2E20 / 15 Jun 2014
Plan 10
S2E21 / 22 Jun 2014
Vengeance is Mine
S2E22 / 29 Jun 2014
A Chinatown Ghost Story
S2E23 / 12 Sep 2014
Into Dimension X!
S2E24 / 19 Sep 2014
The Invasion (1)
S2E25 / 26 Sep 2014
The Invasion (2)
S2E26 / 26 Sep 2014
Season 3
Within the Woods
S3E1 / 03 Oct 2014
A Foot Too Big
S3E2 / 10 Oct 2014
Buried Secrets
S3E3 / 17 Oct 2014
The Croaking
S3E4 / 07 Nov 2014
In Dreams
S3E5 / 14 Nov 2014
Race with the Demon!
S3E6 / 21 Nov 2014
Eyes of the Chimera
S3E7 / 11 Jan 2015
Vision Quest
S3E8 / 18 Jan 2015
Return to New York
S3E9 / 25 Jan 2015
Serpent Hunt
S3E10 / 01 Feb 2015
The Pig and the Rhino
S3E11 / 08 Mar 2015
Battle for New York (1)
S3E12 / 15 Mar 2015
Battle for New York (2)
S3E13 / 15 Mar 2015
Casey Jones vs the Underworld
S3E14 / 22 Mar 2015
The Noxious Avenger
S3E15 / 26 Apr 2015
Clash of the Mutanimals
S3E16 / 03 May 2015
Meet Mondo Gecko
S3E17 / 10 May 2015
The Deadly Venom
S3E18 / 17 May 2015
Turtles in Time
S3E19 / 02 Aug 2015
Tale of the Yokai
S3E20 / 09 Aug 2015
Attack of the Mega Shredder!
S3E21 / 16 Aug 2015
The Creeping Doom
S3E22 / 23 Aug 2015
The Fourfold Trap
S3E23 / 13 Sep 2015
Dinosaur Seen in Sewers!
S3E24 / 20 Sep 2015
Annihilation: Earth! (1)
S3E25 / 27 Sep 2015
Annihilation: Earth! (2)
S3E26 / 27 Sep 2015
Season 4
Beyond the Known Universe
S4E1 / 25 Oct 2015
The Moons of Thalos 3
S4E2 / 01 Nov 2015
The Weird World of Wyrm
S4E3 / 08 Nov 2015
The Outlaw Armaggon!
S4E4 / 15 Nov 2015
Riddle of the Ancient Aeons
S4E5 / 10 Jan 2016
Journey to the Center of Mikey's Mind
S4E6 / 17 Jan 2016
The Arena of Carnage
S4E7 / 24 Jan 2016
The War for Dimension X
S4E8 / 31 Jan 2016
The Cosmic Ocean
S4E9 / 13 Mar 2016
Trans-Dimensional Turtles
S4E10 / 27 Mar 2016
Revenge of the Triceratons
S4E11 / 03 Apr 2016
The Evil of Dregg
S4E12 / 10 Apr 2016
The Ever-Burning Fire
S4E13 / 17 Apr 2016
Earth's Last Stand
S4E14 / 24 Apr 2016
City at War
S4E15 / 14 Aug 2016
Broken Foot
S4E16 / 21 Aug 2016
The Insecta Trifecta
S4E17 / 28 Aug 2016
Mutant Gangland
S4E18 / 04 Sep 2016
Bat in the Belfry
S4E19 / 11 Sep 2016
The Super Shredder
S4E20 / 06 Nov 2016
Darkest Plight
S4E21 / 13 Nov 2016
The Power Inside Her
S4E22 / 20 Nov 2016
Tokka vs. the World
S4E23 / 05 Feb 2017
Tale of Tiger Claw
S4E24 / 12 Feb 2017
Requiem
S4E25 / 19 Feb 2017
Owari
S4E26 / 26 Feb 2017
Season 5
Scroll of the Demodragon
S5E1 / 19 Mar 2017
The Forgotten Swordsman
S5E2 / 26 Mar 2017
Heart of Evil
S5E3 / 02 Apr 2017
End Times
S5E4 / 09 Apr 2017
When Worlds Collide (1)
S5E5 / 18 Jun 2017
When Worlds Collide (2)
S5E6 / 18 Jun 2017
Yojimbo
S5E7 / 23 Jul 2017
Osoroshi no Tabi
S5E8 / 30 Jul 2017
Kagayake! Kintaro
S5E9 / 06 Aug 2017
Lone Rat and Cubs
S5E10 / 13 Aug 2017
Raphael Mutant Apocalypse, Part 1: The Wasteland Warrior
S5E11 / 22 Sep 2017
Raphael Mutant Apocalypse, Part 2: The Impossible Desert
S5E12 / 22 Sep 2017
Raphael Mutant Apocalypse, Part 3: Carmageddon
S5E13 / 22 Sep 2017
The Curse of Savanti Romero
S5E14 / 27 Sep 2017
The Crypt of Dracula
S5E15 / 27 Sep 2017
The Frankenstein Experiment
S5E16 / 04 Oct 2017
Monsters Among Us
S5E17 / 11 Oct 2017
Wanted: Bebop and Rocksteady
S5E18 / 12 Nov 2017
The Foot Walks Again!
S5E19 / 12 Nov 2017
The Big Blow Out
S5E20 / 12 Nov 2017
Seth Green
Leonardo (voice)
Rob Paulsen
Donatello (voice)
Sean Astin
Raphael (voice)
Greg Cipes
Michelangelo (voice)
Mae Whitman
April (voice)
Josh Peck
Casey Jones (voice)
Kelly Hu
Karai
