“THE HOUSE WITH A CLOCK IN ITS WALLS” — 2 stars — Jack Black, Cate Blanchett, Owen Vaccaro, Kyle MacLachlan; PG (thematic elements including sorcery, some action, scary images, rude humor and language); in general release

A great piece of writing can fail dramatically if it doesn’t understand its audience.

Eli Roth’s “The House With a Clock in Its Walls” isn’t a great movie, but issues with reaching its audience keep it from being the fun family option for the Halloween season it feels like it should be.

Set in the mid-1950s and based on the book by John Bellairs, “House With a Clock” follows the supernatural adventures of a young boy as he learns the art of magic. And yes, that does sound an awful lot like Harry Potter.

Also like Potter, “House With a Clock’s” protagonist is sent to live with an eccentric relative following his parents' death. Lewis (Owen Vaccaro) is a brainy 10-year-old who is still teetering on the edge of his childhood. He loves to read the dictionary and is very sharp, but he also insists on wearing goggles at all times in tribute to his favorite TV personality.

After Lewis’ parents die in a car crash, he is sent to New Zebedee, Michigan, to live with his crazy Uncle Jonathan (Jack Black). Jonathan lives in a vast and beautiful Victorian home that is stuffed with clocks, and he keeps jack-o'-lanterns on the front porch year-round. It doesn’t take long for Lewis to realize that his uncle is a warlock, or as he puts it, a “boy witch.”

In time, Jonathan agrees to teach Lewis his magic ways, with assistance from a witch next door named Florence (Cate Blanchett). The training helps ease Lewis’ transition to New Zebedee, which includes a rocky start at a school full of kids ready to bully him at every turn.

The more Lewis learns about magic, the more he learns about his uncle’s unique predicament. The previous owner of the home, an evil magician named Isaac Izard (Kyle MacLachlan), died after leaving a mysterious clock hidden in its walls. Jonathan is determined to find the clock, and as Lewis learns why, he discovers that Izard may still be a threat.

“House With a Clock’s” early scenes are spooky and whimsical, whipping the film’s world to life and evoking memories of Ray Bradbury and Tim Burton. Jack Black is a perfect match for his character, and his inherent goofiness is nicely complimented by Blanchett’s regal grace as Florence (the catty banter between the two is a real highlight). Vaccaro is sympathetic as Lewis, and though there are conceptual similarities to the Potter saga, “House With a Clock” feels unique enough to stand on its own.

But as the film moves forward, digging further into the Izard story, the subject matter gets progressively darker and the story gets messier. Though it never officially crosses into PG-13 territory, “House With a Clock” lingers in enough macabre content — dealing in elements of black magic and featuring some genuinely disturbing animation — to eliminate younger children from the target audience.

Not being familiar with the source material, it’s hard to know if Bellairs’ book is intended for more mature audiences, but regardless, it’s hard to imagine “House With a Clock” appealing to an audience old enough to handle the film’s creepiness. It’s also likely that Roth — better known for hard-R torture-porn horror like “Hostel” and “The Green Inferno” — just hasn’t been able to dial down his usual routine far enough for a family audience. Given the charm of the film's first act, that really seems too bad.

“The House With a Clock in Its Walls” is rated PG for thematic elements including sorcery, some action, scary images, rude humor and language; running time: 104 minutes.