Chapter 57

Tropes That Appear In This Chapter:

The Bus Came Back: Officer Howard makes a reappearance here since the Northampton Arc, having apparently transferred to the NYPD after the various adventures the Kids had out in the country.
For Want Of A Nail: In "Casey Jones VS. The Underworld", Casey Jones Leeroy Jenkins his way into the factory, hoping to take down the Shredder himself. With Miwa there holding him back, they manage to get the other four there and manage to plant bombs surrounding the factory, undoing Shredder's operation.
Internal Reveal: It's here that Leo, Raph and Mikey find out about Casey's crush on Miwa, Donnie having figured it out weeks before.
Knight Templar Big Brother: Played for Laughs. Leo, being the responsible brother, is the most hostile towards Casey when he finds out that he may or may not be dating his sister. He even votes to have Casey plant the bomb inside the factory, this being the most dangerous place to scope out due to the abundance of mutants, foot-bots and The Shredder.
My Sister Is Off-Limits: When they find out that Casey has a crush on Miwa (with feelings that might be reciprocated), Leo, Mikey and Raph have different flavors of this. Leo feels protective of Miwa and feels the need to threaten him, Raph is hurt that his friend didn't tell him (not to mention how it contradicts The Bro Code) and Mikey seems horrified at the idea of her sister kissing someone.
Mythology Gag: The text refers to Hun as a "Bruce Lee Wannabe", a reference to his design purposefully being a Bruce Lee Clone.
Pre-Asskicking One-Liner: Casey gives one to Rahzar and Fishface, who in-turn give him a Lame Pun Reaction.
Casey: The class is Pain 101. Your instructors are Nightwatcher and Armonia. Any questions before we begin?
Rahzar: Did you really just say that, kid?
Worf Had the Flu: The reason why Miwa decides to go help Casey instead of Leo, Raph and Mikey is because they had only just turned back human after months as turtles, so their center of gravity and limitations are thrown out of whack and they have to relearn everything.