In making The Night Listener, director and co-scripter Patrick Stettner would have been well-advised not to overly visualize the story. This is, after all, an adaptation of a book about a radio host’s purely telephonic relationship with an ardent listener. Visual options would seem limited to close-ups of mouths, ears, microphones, headsets, and telephones, perhaps supplemented by the sort of swoop-down-the-telecom-line shots Krzysztof Kieslowski employed in Red. Alas, Stettner decided to “open up” the narrative, thus rendering an intriguingly elusive tale into something that’s as predictable as a teen horror flick.

Based on Armistead Maupin’s semifictionalized tale, The Night Listener is a brief anecdote—expanded to 82 minutes only with the help of copious asides—from the life of a Maupin-like radio talker. Gabriel Noone (Robin Williams) doles out morsels of autobiography in rambling, lyrical raps, but his gift for gab has faltered since his younger lover, Jess (Bobby Cannavale), announced he’s moving out of Gabe’s New York town house. Hoping to divert the radio host’s attention, Gabe’s friend Ashe (Joe Morton) gives him a copy of an unpublished memoir. It’s the harrowing saga of a 14-year-old who was sexually abused by his parents, leaving him emotionally and physically devastated. Now battling AIDS, Pete Logand (Rory Culkin) is a big fan of Gabe’s show—and apparently a precociously gifted writer.

Soon Pete and Gabe are talking regularly, and Gabe wants to meet the boy. But Pete’s guardian Donna (Toni Collette) has abundant reasons why that can’t happen, arousing Gabe’s suspicions. When Jess suggests that Pete and Donna have the same voice, Gabe initially denies it. Yet soon he’s discussing the possibility that Pete is a fictitious character both with Ashe, who rejects it, and with his accountant Anna (Sandra Oh), who’s more skeptical of the boy’s persona. Frustrated by Donna’s series of proffered but then withdrawn invitations, Gabe travels to the wintry Wisconsin town where Pete and his protector supposedly live and tries to enlist the help of various uncooperative locals. Ultimately, Gabe breaks into Pete and Donna’s home, in a sequence that exemplifies what’s wrong with the movie: Stettner doesn’t trust Maupin’s ambiguous premise, so he embroiders it with the usual old-dark-house ploys, including deep shadows, eerie sounds, oblique camera angles, and shock cuts. The director might as well have installed a Jason or Freddy in the basement, waiting for Gabe to blunder down the stairs.

As the well-meaning radio host who’s finally hailed for his “great-big heart,” Williams suppresses his manic side, a maneuver that used to be impressive but now is a well-established alternative to his Mork-isms. The film belongs to the protean Collette, an actor playing a woman who is a very accomplished actor. One of the most vivid in Collette’s gallery of grotesques—a group that does not include her role in this week’s Little Miss Sunshine, a movie that’s practically a vacation for her dark side—Donna is the story’s mystery personified. When she’s on-screen, which by definition can’t be much of the time, the film is creepily alive. The problem is that most of what Stettner does to underscore Collette’s uncanny presence is so formulaic that it diminishes rather than amplifies the mood. The Night Listener may begin as a tantalizing psychological riddle, but it ends as the sort of haunted-house show Zak Bedderwick would understand.