While jogging through the city's sewers, the five Turtles find an animal cage holding a live endangered baby hawksbill sea turtle. The TMNT discover the man responsible for capturing the little terrapin -- Simon Bonesteel -- just as the poacher is about to sell the baby turtle to a dealer in illegal wildlife trade. After a brief introductory skirmish with Bonesteel and his overcoat's seemingly endless arsenal of weaponry, the Turtles manage to escape with the young hawksbill. Bonesteel, however, is far from beaten and vows to take up the hunt--- the hunt for Ninja Turtles!
The TMNT are barely a few sewer blocks away when Bonesteel attacks anew. The fight is fast and furious as Bonesteel proves to be as much a physically powerful street brawler as he is adept at using bull whips, crossbows and steel net snares. Seeing that they appear to be evenly matched, the TMNT and Bonesteel agree to a truce of sorts. Each side going their respective ways; the Turtles with the baby turtle and Bonesteel with his dignity.
It isn't until several sewer blocks later that the TMNT realize that Bonesteel had tricked them, somehow making off with the infant hawksbill!
After careful consideration, and a quick education about the perils of illegal trade in endangered turtles and the legal (though no less deadly) turtle pet industry, the five Turtles decide to hunt the hunter, and hunt Bonesteel they do, poaching the poacher and saving the baby sea turtle, while seeing the commonality that they share with the Earth's endangered species.
Bonesteel, of course, again vows to return and take up the hunt again --- the greatest of all hunts, the hunt for the world's only five mutant turtles!