The Boogeyman is back to threaten the Guardians and the children of Earth. And the Man in the Moon has decided that Jack Frost is to join the fight against darkness and fear.
While Jack doesn't do anything bad for the sake of being bad, some of his jokes aren't the nicest and one is most definitely dangerous. However, he does know right from wrong in the grand scheme of things and joins the right despite his loner mentality and his doubts. North (Santa Claus), Tooth (the Fairy, that is), (Easter) Bunny, and the Sandman are established good guys. Bunny can be a bit hurtful, but grows to accept the new Guardian. Pitch is the established bad guy and acts as such.
The Man in the Moon seems less God-like here than in the movie, though he still is above the Guardians. The Guardians themselves are people of mythical powers reliant on the belief of children. Up until a certain point, Jack's staff is his source of power.
The bumps, pains, and fights are less intense here than the movie portrays them. In fact, North's sword and Sandy's whips aren't even mentioned until the end. Jack takes a kid on a careening sled ride through the busy streets, ending with a landing in the snow and a sofa hitting said kid (the only harm being the loss of a tooth). All characters are unharmed (though Jack does feel pain from one particular hit).
Drug and Alcohol Content
The "mini fairies" swoon over Jack a couple times, but nothing more.
Crude or Profane Language or Content
The characters are interesting and story itself is fun enough, but the movie's plot races when transferred into easy writing, making for a fairly inclusive but not hugely stimulating read. Morality is pretty basic black-and-white here, though the implications of the belief-in-the-Guardians element may give some parents pause.