Thriller? Comedy? If only ...

Johnny Depp and his hairdresser work overtime in the goofy thriller “Secret Window,” and it’s a tossup which guy has come out looking better for his efforts. Depp stars as Morton Rainey, a writer who’s gone down the emotional rabbit hole after separating from his wife. Tucked away in the countryside with only a milky-eyed dog for company, Mort has all but shut out the outside world, a condition and a genre conceit that all but assures that it’s just a matter of time before something or someone comes banging on his door with a vengeance.

Trouble appears in the person of John Shooter (John Turturro), wearing a wide-brimmed black hat and carrying a battered manuscript and a grudge as weighty as Cain’s.

A Mississippi dairy farmer with a molasses-drip voice, Shooter lands on Mort’s porch uninvited and unwelcome, claiming that the successful author has stolen his story. Mort denies the plagiarism charge and brushes the interloper off, setting off a violent chain of events that eventually involves some household tools, the local law (Len Cariou), a private investigator (Charles S. Dutton), the writer’s estranged wife (Maria Bello) and the wife’s clueless boyfriend (Timothy Hutton). Things go bump in the night, dogs howl, people scream and houses disintegrate along with one transparently addled mind and one very thinly realized story.

Directed with loud comic undertones by David Koepp, a familiar studio go-to guy (his writing credits include “Panic Room”), and based on a novella by Stephen King, “Secret Window” opens with a close-up of Depp and rarely strays from the actor in the scenes that follow. The strategy proves to be one of the film’s strengths as well as one of its major weaknesses. Although Koepp tosses in a few flashbacks and some off-site scenes, much of the film’s action unfolds inside Mort’s country house, a space that -- much like the Overlook Hotel in King’s “The Shining” -- assumes escalating metaphoric resonance. King knows that a creative refuge can easily become a penal colony, especially for someone devoted to a life of the mind, but as a writer he’s careful to make sure it doesn’t become a narrative prison as well.

Koepp has it tougher than King with this story partly because the medium in which he’s working doesn’t bend easily to stories hinged on the life of the mind. The director keeps up a busy front, mostly by tagging after his star, but there are limits to what each can do with the material. A character actor at heart, Depp likes to dig under the skin of a character -- either by retreating into Zen-like blankness or letting his eccentricities rip -- but there isn’t much for him to chew on here. Of course, playing a guy named Mort sounds as if it might pose a challenge for this blissfully exotic bird, but because “Secret Window” hinges on a nominal mystery, the actor is forced to keep his wilder side, if not his hair, in check.

That doesn’t mean that it isn’t fun to watch Depp, only that it’s not fun enough considering his gifts and what Koepp seems to have in mind for the film. Unsteadily pitched between horror and comedy, “Secret Window” turns out to be neither terribly scary nor especially funny. Unlike King, a master of ambiguous intention, Koepp seems caught between self-amusement and a desire to scare the stuffing out of the audience, and as a consequence he never finds the right tone, a perilous shortcoming in a thriller. Still, Depp fusses through the film with restrained superfluity, nervously clutching at his tatters like some latter-day Miss Haversham. When Shooter comes a-knocking, essaying a crude variation on Robert Mitchum in “The Night of the Hunter,” you half expect Mort to greet his gentleman caller with a smile.

*

‘Secret Window’

MPAA rating: PG-13, for violence and terror, sexual content, language

Times guidelines: bloody violence against an animal and some people

Johnny Depp...Mort Rainey

John Turturro...John Shooter

Maria Bello...Amy

Timothy Hutton...Ted

Charles S. Dutton...Ken Karsch

Columbia Pictures presents a Pariah production, released by Columbia Pictures. Director and screenwriter David Koepp. Based on the novella “Secret Window, Secret Garden” by Stephen King. Producer Gavin Polone. Director of photography Fred Murphy. Production designer Howard Cummings. Editor Jill Savitt. Costume designer Odette Gadoury. Depp hairdresser Martin Samuel. Music Philip Glass. Running time: 1 hour, 37 minutes.

In general release.