Splinter allows the Turtles to visit the surface for the first time, where they attempt to stop a group of thugs from kidnapping April O’Neil and her parents. But the Turtles, who have never been in actual combat before, fail miserably. Splinter, realizing that the Turtles need a leader, assigns the task to Leonardo. After some initial resistance, especially from Raphael, Leonardo’s leadership skills begin to take shape. The Turtles track down Snake, one of the kidnappers, and when they come upon a mysterious canister of mutagen (the same kind of mutagen that transformed the Turtles and Splinter 15 years ago) they realize this mystery is much bigger than they ever imagined...