Fifteen years have passed since a rat named Splinter found four baby turtles in a puddle of ooze in the sewers. Because of the contact with the ooze, Splinter and the four turtles became mutants. Naming them after Renaissance artists, Leonardo, Raphael, Michaelangelo, and Donatello, Splinter teaches them the ancient secret art of fighting. When the mysterious evil Shredder organizes the Foot Clan formed of young teenagers, causing the city to be in uproar because of vandalism. With the help of reporter April O'Neil and former athlete Casey Jones, it's up to the Teenage Mutant Ninja Turtles to save the day! The Turtles, investigating a strange blackout, discover the Foot Ninja stealing a Japanese ceremonial sword from the Metropolitan Museum of Art. The sword turns out to have incredible powers, able to create powerful vibrational shockwaves. Investigating another blackout, the Turtles discover the Foot Ninja have hooked up the sword to a high-tech cannon apparatus for some nefarious purpose. The Turtles battle more Foot Ninja, but now they must shut down the vibrational cannon, which threatens to topple a good chunk of lower Manhattan. After Casey Jones makes himself an unwanted guest in the Turtles' lair, Raphael takes him topside for a 'breath of fresh air', where they encounter the Foot Tech Ninjas, enhanced with cyber armor that makes them faster, stronger and able to cloak themselves to virtual invisibility. Raphael is kidnapped and interrogated, but Casey manages to slip away and warn the other Turtles. Raphael escapes his captors but, unbeknownst to him, is tailed by a squad of cloaked Foot Tech Ninjas. Will Casey and the others get to Raphael in time before he leads the Foot Tech Ninja directly to the Turtles' lair? Shredder attempts to convince Leonardo that the Shredder is fighting the good fight, that he's out there carrying on the great tradition of Bushido and Ninjitsu, and the turtles should stand with him. Leonardo is taken in and almost convinces the others until Splinter reveals what he knows of Shredder and Hun, mainly how they did away with Splinter's Master Yoshi. Leonardo realizes he's been fooled and, it's never a good idea to fool a turtle, at least not a teenage mutant ninja one. Our four turtles stand facing their most formidable foe to date, the Shredder. Battle weary, the turtles cannot stand against the Shredder and manage to slip away, getting separated in the process. Can they survive apart? Can they get back together in time to save themselves and face the Shredder? Maybe, with Master Splinter there to guide them...