With the Turtles back and New York City is free from the Krang occupation, life should be returning back to normal, but Casey notices that crime is still growing and the Turtles aren’t doing anything about it. He also feels pushed aside when the Turtles fought the Krang in Dimension X, and wants to feel like he is making a difference in protecting this city.
As the Turtles return to their old lair in the sewers, Jones vents out his frustration that the Turtles aren’t doing enough to protect this city. 
The Turtles just brush it off and reminds Casey they saved millions of New Yorkers from the Krang and needs a rest. While patrolling the streets, Casey notices an old enemy causing trouble in Chinatown. A new leader emerges that has taken over the Purple Dragons. A wanna be Bruce Lee kung fu master by the name of Hun. He fights with the style of Bruce and even talks like Bruce. Casey tries to stop their criminal act but gets schooled by Hun. Bringing in a new face and character is good and I think Hun will be a wonderful homage to our favorite kung fu master.
Casey finds out that Shredder is making a power play within the criminal underworld. He discovers that Shredder has already cornered the Russian, Asian, and the South American mafia in New York, and he desires to take control of the Italian mob. With the Krang gone, Shredder can do more damage than before and Casey tries to tell Raph about Shredders plan. I love Casey’s enthusiasm and guts when trying to fight crime. When he stops Fishface and Tigerclaw from stealing a briefcase full of dangerous chemicals, Raph jumps in and helps Casey. Their encounter is somewhat not friendly due to the fact that Raph yelled at him and treated him like a weak victim. They separate on heated terms while Raph brings the case to Donnie for more examination, while Casey is going after Shredder.
Casey does a great job investigating and following his hunches about Shredder’s plan and how the Purple Dragons are involved with helping Shredder giving him the equipment and resources to accomplish his goal. 
At this point in the episode, I’m not sure what Shredder has in store with those dangerous chemical, but it needs a large manufacturing plant and a large distribution network throughout the city.
The final battle between Casey and Shredder at the chemical plant in Chinatown is great. The plant looks like a game show from hell with many sharp chomping objects ready to bite anybody in half. The Turtles finally show up and help Casey stop the Purple Dragons and Shredder from moving forward with their evil plan. Unfortunately Donnie finally understands why Shredder needed this chemical plant. It is a way to manufacture and distribute the mind controlling substance, that he obtained from the Purple Dragons, to everybody in New York, including Karai.
Today Casey is the hero. He stopped Shredder from mass producing a mind controlling chemical, and he went face to face with Shredder and survived. For a non mutant, he is pretty bad ass.
