The mutant outbreak continues to spread throughout the sewers and subway tunnels while the Turtles try to contain the threat. Back at Area 51, Baxter Stockman prepares a new body for cerebral transfer despite warnings from Agent Bishop. When Stockman’s body begins to show signs of rejection, he becomes delirious, which leads to a rampage against the person he believes to have caused all his problems, April O’Neil.

.TMNT 2006 S04-E19 “Insane In The Membrane” 1/2

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Popularity: 3%

April discovers a distress signal from her Uncle Augie, who became trapped in another dimension years ago. She appeals to Donatello for help and they use April’s puzzle cube to travel across the multiverse. They find Augie, along with his new lizard-like friends, the Brotherhood, who claim they wish to help the inhabitants of Earth. Unfortunately, they soon discover the Brotherhood’s true aspirations are not so benevolent.

.TMNT 2006 S04-E18 “Trouble With Augie” 1/2

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Popularity: 5%

Following the invasion engineered by Agent Bishop, genetic material from the replicated aliens combines with inhabitants of the sewers and surrounding waterways, causing a mutant outbreak. Fearing the spread of outbreak, Bishop sends Baxter Stockman to contain the threat. Meanwhile, the Turtles search for items to furnish their new lair, but now must face the threat of attacking mutants.

TMNT 2006 S04-E17 “Outbreak” 1/2

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Popularity: 6%

Leonardo returns home to find the lair in ruins and his family missing. His search for answers and his family eventually lead him to the realization that Karai is no longer an ally.
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Popularity: 6%

With Leonardo gone, Splinter, Raphael, Donatello and Michelangelo witness the return of the Shredder. They are plunged into the fight of their lives as they ward off volleys of Foot Ninja and Foot Mechs that lay waste to their lair.
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.TMNT 2006 S04-E15 “Scion of the Shredder” 1/2

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Popularity: 7%

When Leonardo’s anger causes him to injure Splinter, he seeks redemption by travelling to Japan. There, he begins a quest to find the Ancient One, who once trained Splinter’s sensei, Hamato Yoshi.
.TMNT 2006 S04-E14 “The Ancient One” 1/2

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Popularity: 7%

Master Splinter invites Miyamoto Usagi—and the irresponsible, sloppy Murakami Gennosuke—from their dimension to Earth in the hopes that Usagi can speak to Leonardo about his wayward attitude. When Gen wanders off to explore downtown Manhattan, the Turtles, Usagi and Casey set out to find him. Their search becomes complicated when an assassin, sent after Leonardo by Lord Hebi, follows Gen and Usagi to Earth.
.TMNT 2006 S04-E13 “Samurai Tourist” 1/2

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Popularity: 8%

The Turtles are preparing to celebrate Halloween—one of the few times in the year where they can be seen in public. When costumed thieves steal a statue from April’s antique shop, the Turtles put aside their jack-o’-lanterns and pursue them. This theft is part of a bigger plan by a sorcerer, the King of Thieves, who plans to use the statue to unleash a legion of minions on the city. When the Turtles come to disrupt his plans, the sorcerer summons the Thievery God, bringing the statue to life; it then sets out to destroy the Turtles.
.TMNT 2006 S04-E12 All Hallows Thieves 1/3

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Popularity: 10%

Nobody returns and reaches out to the Turtles to help him stop his foe, Ruffington, and the Purple Dragons from selling weapons to a violent street gang, the Turks.
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Popularity: 9%

As Hun expands the Purple Dragons’ power via illicit arms trades, the Turtles and Casey Jones seek to stop him yet again. Leonardo continues to unduly press his brothers while Casey seeks revenge on Hun for causing a tragic event during his childhood.

.TMNT 2006 S04-E10 “Dragons Rising” 1/2

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Popularity: 10%