Title Reference: The Maltese Falcon In the middle of a summer heat wave, someone is destroying all the air conditioners and taking all the city's freon.
Meanwhile, Shredder and his mutant goons, Bebop and Rocksteady, are also there, but to collect a crystal needed by Krang to recharge the power cells of the Technodrome.
Emperor Aleister of Malicuria comes to the United States with a sample of Lydium 90, which gets noticed by Krang as a way to power up the Technodrome, which has constant brownouts.
To celebrate relations between Malicuria and the US, the Emperor hosts a masquerade ball in New York, but his bored daughter and April's exact double, Princess Mallory sneaks out for a night on the town.
Title Reference: Twenty Thousand Leagues Under the Seas Worried that Shredder will soon win, Leonardo takes some time off, doubting his leadership.
Meanwhile, Krang and Shredder drain solar energy from the Sun for the dual purpose of powering the Technodrome and capitulating Earth into another Ice Age.
A visit to Earth from a Polarisoid results in havoc when Shredder (and later, April O'Neil) comes into possession of the alien's camera, because it does more than just take pictures.
Donatello races for an antidote before Shredder drains a naval nuclear submarine of all its power, and things get crazy when Rocksteady takes a dose of the potion and falls in love with April.
Splinter suffers amnesia as the Turtles try to remind him that he is the true leader of the Foot Clan by reminiscing on their earliest adventures.
After Master Splinter's favorite kimono is stolen, April's famous detective aunt helps the Turtles retrieve it.
Leatherhead arrives in New York seeking revenge for his defeat only to run into the Rat King who captures him and reveals his plans for world domination.
Meanwhile, the Turtles search for Michaelangelo with an antidote for the anti-mutagen before it destroys him, while Shredder's two mutant goons ask for help from their old gang to rob a ship.
An interdimensional alien spacecraft leads Baxter Stockman to his latest vengeful plot to destroy the Turtles and Shredder.