When the keys to a film being a success depend on a trio of 12- and 13-year-old children and Kenneth Branagh, the odds of the film being a horrific failure of the grandest scale border on absolute certainty.

Even worse, when the success of such a film also hinges on pleasing the most fickle of fans that have read the book upon which the film is based, the odds are even worse.

However, it is “Harry Potter and the Chamber of Secrets” that proves such a success is possible. In fact, it might be that film that librarians dread seeing — a film that far outshines its source material.

While the book seems often a rehashed version of the first, with an ending that reeks of “Harry Potter and the Sorcerer’s Stone,” the second film is bound to make anyone forget the first film. The sets are magnificent, the acting substantially improved and the script far smarter and better at adapting J.K. Rowling’s work than the first.

The story of the second book and film is simple. Harry is warned not to return to Hogwarts because bad things are about to happen. Hogwarts has replaced professor Quirrell with the pompous and incompetent Gilderoy Lockhart, who teaches from only his own books, yet can’t seem to muster any ability when called upon to do so. It is revealed that the chamber of secrets that Salazar Slytherin had created has been opened and that the students are in danger.

The story comes to life largely because the sets and art direction of the film are breathtaking, and provide some of the most humorous moments, particularly with the use of portraits and photos in the film. While they are wondrous to look at, they stop short of the excess that had harmed films like “The Lord of the Rings: Fellowship of the Ring” and “Star Wars Episode II,” simply functioning as an entertaining backdrop rather than the main character.

The acting has substantially improved in the second film as well, with Daniel Radcliffe growing nicely into the role of Harry Potter. Twelve-year-old Emma Watson has a smaller part as Hermione in this film, but she hits all the right chords again. Only the excessively evil Draco Malfoy (Tom Felton) and the sniveling Ron Weasley (Rupert Grint) seem off the mark, and this is likely to be because of Rowling’s child-focused material more than the child stars.

In the role of Gilderoy Lockhart, Branagh is a natural. Few could show the smugness the part demanded, but he manages it perfectly. Unlike Branagh’s wretched attempt to play Woody Allen in “Celebrity” and his phoned-in role in the almost unmentionable “Wild Wild West,” Branagh finds a character that suits him perfectly in the professor whose claims are incredible, but whose actual abilities are limited to running away from adversity. He makes such an impact in his minimal role that he warrants serious Academy Award consideration.

If there is one gripe about the film, it’s that there are actually three. Sure enough, there are — though none of them detract from the film too terribly.

First and foremost, without a doubt, the first film had moments where the most conservative of parents could have said that it was clearly not a children’s film. In this film, however, they might not be able to find any, because it never once resembles a children’s film.

The language is clean — there’s obviously no 13-year-olds engaging in NC-17 rated behavior — but the film is intense and I can’t imagine any child under 10 not being frightened by the loud noises and surprisingly tense action sequences. More often than not, the closest comparison to this film is “Jurassic Park.” Watch in particular the sequence when Harry and Ron’s car gets stuck in a tree, and the comparison seems obvious. The Quidditch sequence will also remind almost anyone of “Star Wars.”

Secondly, the ending is so saccharine that it is known to give cancer to lab animals. While this can be expected to a certain extent, they even employ Bad Movie Motif No. 1 — the slow clap.

Thirdly, and this is definitely in the realm of nit-picking, John Williams’ score is just too much. Though grandiose in scale, it gets in the way of key sequences in the movie simply because it eliminates any doubts as to what may happen. It comes off too heavy-handed, holding the audience down and them pummeling them into submission with music.

Nonetheless, the film is a tremendous accomplishment and will serve as a pleasant surprise to those who have read the book, and possibly convince those few stragglers who haven’t that it’s time to head to their local elementary school library.

Though “Harry Potter and the Chamber of Secrets” isn’t the best film of 2002, it’s in some elite company. If not one of the top five films of the year, it is at least one of the finest sources of pure entertainment.