If there's a lesson to be learned from the fantasy adventure "The Seeker," it's that when Ian McShane tells you not to do something, you really should listen.

In this dreary, spectacle-driven adaptation of "The Dark Is Rising," the second novel in Susan Cooper's award-winning fantasy series for young adults, the stentorian-voiced English actor, late of "Deadwood" fame, plays Merriman Lyon. As one of the Old Ones, a quartet of immortal warriors, Merriman tutors young Will Stanton (Alexander Ludwig) in the ways of the Light and the Dark and lays out the tremendously important task that is his destiny. Will learns everything the hard way, usually by disregarding Merriman's advice.

John Hodge's script diverges fairly significantly from Cooper's book, most notably in changing Will from an 11-year-old English boy to a slightly older American whose family has recently relocated to a small town in the United Kingdom. The seventh son of a seventh son (with all the baggage that the numerology apparently implies), Will awakens on his 14th birthday and discovers he has heightened senses that can turn a visit to a mall into something resembling a bad drug trip.

He soon learns from Merriman and the other Old Ones, who include Frances Conroy as Miss Greythorne, that he is one of them, the last in a line of warriors empowered to save the world from the evil forces of the Dark. Will's role as the Seeker is to find the six signs, small circles marked with crosses, each one made from a different material, before the Dark's envoy, the Rider (Christopher Eccleston), can acquire them.

Time is of the essence, as the Rider's powers increase over the five days in which Will has to find the signs, presaged by increasingly bad weather -- even by English standards. The signs are hidden throughout history but, fortunately, one of Will's powers is the ability to step through different epochs and return just as quickly.

Like many a fantasy protagonist, Will has powers that coincide with the onset of puberty and manifest in ways such as the huge explosions of fire that erupt as he experiences frustration over his lack of success with an older girl (Amelia Warner) who captures his fancy. The character's age and supernatural abilities invite unflattering comparisons to the "Harry Potter" films, which do a much better job of making this type of myth-driven story compelling.

There are hints that this might have once been a more character-driven project, as the first part takes its time in introducing Will's situation and his large family before launching into a hectically paced middle and end. Rather than giving the film a sense of urgency, the chaos dilutes the story's English folklore roots, making it feel more generic.

What made it to the screen is stripped down to its action essentials, skipping ahead from one effects-laden clash to the next. It feels as if entire reels have been dropped. Director David L. Cunningham (TV's "The Path to 9/11") applies a jarring, disorienting style to much of the action that, rather than mirroring Will's inner confusion, distances the audience from his plight.

kevin.crust@latimes.com

"The Seeker." MPAA rating: PG for fantasy action and some scary images. Running time: 1 hour, 39 minutes. In general release.