Owari

Owari is the twenty-sixth episode of the fourth season of Teenage Mutant Ninja Turtles as well as the season finale, and the 104th episode of the series overall.

Synopsis
With the demise of their beloved father and Karai incapacitated, the Turtles, April, and Casey, infiltrate Super Shredder's new lair to put an end to Oroku Saki once and for all, no matter what it takes.

Major Characters

 * April O'Neil (Mae Whitman)
 * Casey Jones (Josh Peck)
 * (Rob Paulsen)
 * (Seth Green)
 * (Greg Cipes)
 * (Sean Astin)
 * Splinter's Spirit (Hoon Lee)
 * Super Shredder (Kevin Michael Richardson)

Minor Characters

 * Bebop (J.B. Smoove)
 * Chompy Picasso
 * Dr. Cluckingsworth
 * Elite Footbots
 * Fishface (Christian Lanz)
 * Footbots
 * Ice Cream Kitty
 * Leatherhead
 * Karai (Kelly Hu)
 * Kirby O'Neil
 * Pigeon Pete
 * Rocksteady (Fred Tatasciore)
 * Shinigami
 * Slash
 * Stockman-Fly/Baxter Stockman (Phil LaMarr)
 * Tiger Claw (Eric Bauza)
 * Tyler Rockwell

Plot
At the farm where the Turtles, April, and Casey had retreated to back during the Kraang invasion, they, alongside Shinigami, the Mutanimals, Kirby, and other friends and allies, pay their final respects at Splinter's grave. Some time later, Leo is meditating when he has a vision of Splinter who encourages him to fight the Shredder one last time to ensure he is no longer a threat. After some thought, Leo decides Shredder's reign of terror ends now.

Back in NYC, the Turtles visit Karai at the hospital. She's suffered numerous cuts, bruises, abrasions, and has a broken arm, but will recover. As the Turtles ask for her help to take down Super Shredder for good, she provides them the location of Super Shredder's hideout, knowing they will take him down and avenge her father's murder.

Back in their lair, the Turtles, April, and Casey suit up for battle, and with a cry of "BOOYAKASHA", they head for Super Shredder's hideout.

After dodging the various surveillance cameras and booby traps, the Turtles eliminate the Foot-bot defenses, before being confronted by Elite Foot-bots, who soon trap them on a cliff before pushing them into the water to fight them there alongside Fishface. However, April is able to get Fishface on shore, where Raphael destroys his legs and removes his breathing apparatus, leaving him to suffocate as they head back to Shredder's hideout.

Once inside, they first run into Stockman, whom Mikey shuts up by using one of Donnie's retro-mutagen vials to return him to normal, then knocks him out when he complains about finally being cured of his mutation. They then deal with Bebop and Rocksteady, soon managing to turn their own weapon systems against them, but upon reaching the next room, are confronted by Tiger Claw, now sporting an interchangeable prosthetic hand to replace the one Alopex chopped off previously. When Tiger Claw makes the mistake of insulting Splinter's memory, he's soon bested and surrounded, but activates a trapdoor, allowing him to fight the Turtles, April, and Casey outside, but Leo manages to use his bow and arrows to damage Tiger Claw's rocket pack, sending him careening to the ground below, while the gang soon see the Super Shredder himself, who tosses down a couple of Molotov Cocktails to separate Casey and April from the Turtles. As the Turtles prepare to do battle with him, Super Shredder flings off his tattered cape and engages them personally.

Despite their best efforts, and not even Donnie's remaining vial of retro-mutagen having any effect on reverting Super Shredder to normal, Raphael, Mikey, and Donnie are soon separated from Leo, who faces Shredder alone. At one point, Leo tries to reason with Shredder, trying to convince him he's become a demon, a monster. As Saki hesitates and takes Leo's words into consideration, Leo tries to attack again, but Shredder overpowers him and prepares to finish him off once and for all and join Splinter in death. However, remembering what Splinter's vision told him, Leo avoids the ending blow, retrieves one of his katanas, and delivers a powerful fatal strike at Super Shredder. Below, the rest of the Turtles, April, and Casey wait, fearing for Leo's life, before Leo appears, injured, but holding the mutated Kuro Kabuto, declaring that the Super Shredder is finished as he tosses it to the ground.

Back in Manhattan, the Turtles, April, Casey, and Karai sit on a rooftop, relieved that Shredder's threat is gone for good, but know that Tiger Claw, Bebop and Rocksteady, and many other bad guys are still out there, waiting to fill the gap that the Shredder's demise has left behind, but know that they will be ready for them, and they have Splinter watching over them from the afterlife with pride.

Trivia

 * "Owari" translates as Japanese for "The End"
 * This episode aired on December 30th in South Korea.
 * In the climax of the final battle, Leonardo slices off Super Shredder's head, finally killing him, which is a reference to the Mirage comic issue #21, where Leo sliced Shredder's head off.
 * In the climax of the final battle, Leonardo slices Shredder head off, finally klling him, which is also a reference to the episode Return to New York, Part 3.

Gallery

 * Owari/Gallery