Summer vacation is over, the Hogwarts School of Witchcraft and Wizardry is back in session, and everyone has grown up a bit. Harry Potter (Daniel Radcliffe) is a little older, a little taller, and his voice is a little deeper. In fact, everything about Chris Columbus’ “Harry Potter and The Chamber of Secrets” — the latest installment of the Harry Potter series — has matured. Clocking in at nearly three hours, the film is longer, the cinematic style is crisper, the digital animation more advanced, and it’s much scarier.

In “Chamber of Secrets,” Harry Potter, the famously scarred boy-wizard is back to solve yet another mystery within the gothic Yale-like walls of the Hogwarts School. This time, Harry — along with his pals Ron Weasley (Rupert Grint) and Hermione Granger (Emma Watson) — seek the culprit behind a series of fatal attacks that occur at the school of magic. The mysterious chamber of secrets is opened and rumor has it that its occupant, a fearsome monster, will unleash horror to purge the school of mugglebloods (wizards of mixed breeding). The search is on to find the heir of the chamber, open it, and vanquish the terrible monster. Or else Hogwarts will be closed forever.

Due to its spookier plot, “Chamber of Secrets” has an element of fear that is absent from its predecessor. Harry’s life is constantly threatened. He hears haunting voices whispering, “kill, kill”; he sees ominous messages written in blood on the school walls. And he even follows an army of spiders into a creepy cave where he nearly loses his life. Everyone at Hogwarts fears the worst. Dobby, the comedic-but-irritating masochistic house elf, claims, “terrible things will happen at Hogwarts.”

Dobby is proof that the series’ digital animation has vastly improved since “Harry Potter and the Sorcerer’s Stone,” the first film in the series. The Quidditch game, ridiculously unbelievable in the first film, is convincing in “Chamber of Secrets” and full of exciting choreography (especially a flying broomstick chase under the bleachers.) Perhaps the most fearful digital inclusion in the film is the massive basilisk that Harry battles in the depths of a subterranean cave. Greatly resembling “Jurassic Park’s” T-rex — but in snake form — the huge serpent, bloody-eyed and wailing, swerves through its lair in pursuit of intrepid Harry.

Also refined is the cinematography, luminous and smoother than in “Sorcerer’s Stone.” It often seems to float as if the camera itself were riding its own Nimbus 2000 broomstick. New human characters join the technological improvements in “Chamber of Secrets.” Most notable is narcissistic Professor Gilderoy Lockhart (Kenneth Branagh) who struts about, sporting gilded robes and teaching Defense of the Dark Arts. Draco Malfoy’s towering father, Mr. Malfoy (Jason Isaacs playing the ideal Aryan), also makes several frightening appearances, intimidating Harry with his piercing eyes.

Though scary at times, “Chamber of Secrets” is also rich with wry humor. This biting wit is hugely present in J.K. Rowling’s books but absent in “Sorcerer’s Stone.” Much of the film’s comedy is due to Grint’s performance as Ron Weasley. His expressive face and cracking voice is hilarious, as are his failed attempts at performing spells with his broken wand. And Errol, Ron’s clumsy messenger owl, adds a lot of humor to the film when he continually slams into windows or tables.

Like the owl’s comedic asides, Columbus dutifully includes many of Rowling’s anecdotal details in the film. But while Rowling briefly delineates idiosyncracies of the world of wizards before delving into the plot, Columbus labors over them, slowing the camera’s movement to capture everything as if it were a department store display. Though the book reads at an incredible clip, offering an intricate view of Hogwarts, the film — though rich in action — moves at a plodding pace.

As an adaptation of a great novel, “Chamber of Secrets” suffices, but only that. Because of the pressure to please innumerable hordes of 10-year-olds, Columbus limits his role to that of an adapter, not an author. In the narrow space to make a lucratively successful and satisfying movie out of an obscenely popular book, Columbus does a good job. But unless Columbus (or the director who will take his place in the third film) finds a way to free himself from the bondage of bookish children everywhere, it is to the very pages that we will have to turn to taste the true magic of Hogwarts.