The Crooked Ninja Turtle Gang were a gang of martial arts students from Smash's Slash For Cash Gym. Shredder, who had been punished by Krang for his failures, denied him access to the Foot Soldiers or the aid of Rocksteady and Bebop until he could prove himself otherwise. With such limitations, Shredder reverted to his prior ways, training human underlings his martial arts ways and ordering them to commit crimes, just as he did in his native home of Japan when he usurped the Foot Clan from Hamato Yoshi. Shredder's plan was to make money from the crimes, but also to damage the reputation of the actual Turtles to the extent they would be forced into the open to clear their names. April warned the Turtles if the imposters are not stopped, soon the NYPD would be on a manhunt for the Turtles, and when the Turtles saw videotapes of the robberies that the gang was trained in the ways of the Foot Clan. Only two senseis were suspect in this, Shredder, or Hamato Yoshi. Since the Turtles were doubtful Splinter would be training enemies, this only left Saki, and the Turtles realized that Shredder had returned from his banishment to Dimension X.
The Crooked Ninja Turtles Gang confronted the real Turtles in a junkyard. The good Turtles easily defeated the impostors. They saved their fight with Smash, the gang leader, for last. Rather than attack him, they tied him up, seeing him as more of an intelligence asset than an enemy. They spared Smash on the basis that he reveal Shredder's whereabouts. At the Slash 4 Cash Gym, Shredder had taken Splinter prisoner. Although captured, Yoshi calmly confronted Saki about the test of who is the better sensei, as evidence by which students would win the fight. Saki admitted he was the worse teacher, as he lacked confidence the Crooked Ninja Turtles Gang could beat the Ninja Turtles.