The events of Leonardo Returns are more or less identical to how they are portrayed in the film it is based upon. The book's plot revolves around the Turtles finding Karai and The Foot battling a monster. However, some details have been changed. The "Ninja Tag" scene, which was not in the final film, is left intact. Furthermore, instead of Bigfoot, the Turtles and Foot encounter Lupa the Werewolf, which is only seen in the books based on the film.