Apocalyptic horror meets Mad Libs in "The Signal," a story of chaotic violence created by three writer/directors who collaborated only in the loosest sense. Atlanta-based David Bruckner, Dan Bush and Jacob Gentry each worked on a third of the 99-minute film without consulting one another. They began with an extreme situation: A brain-scrambling signal emanating from TV sets, radios and cell phones triggers mass psychosis in Terminus City. Almost everyone becomes a homicidal maniac.

Through this maelstrom, they track three interrelated characters: adulterous Mya Denton, her lover, Ben Capstone, and her suspicious husband, Lewis. Every other creative decision was up for grabs. The result is a three-layer cake that's at first succulent, then soggy and finally stale.

The film starts strong, with illicit lovers Mya and Ben justifying their affair. They're guilty yet sympathetic. She is unfulfilled, he is romantic, and Lewis seems more engaged with his widescreen TV and no-account buddies than with his wife. The tension rises as she returns to their apartment, lying about the liaison, while Lewis, who senses he's being double-crossed, tells her he loves her. The evasive dialogue, the details of the pair's fractured relationship provide an undercurrent of unease; when the mysterious signal strikes, it's as if Mya's duplicity triggered a chain reaction in the city's communication devices.

Lewis' pals were childishly swinging a baseball bat while watching the tube; that Louisville Slugger is soon slick with blood and brain matter. The apartment complex becomes a highrise charnel house, and Mya plays a terrifying game of hide-and-seek in the hallways. Lead-off director Bruckner keeps us off balance, unsure whom Mya can trust or what's lurking around the next corner. Anessa Ramsey and A.J. Bowen make a strong impression as the troubled couple, and Justin Welborn strikes a complex note of caddish bravery as her lover.

The problems begin with the second-act plot twist. Instead of a graceful story arc, we get a squiggle. Mya goes AWOL in a farcical segment that is part "Saw," part Three Stooges. For the next 30 minutes, the focus turns to a new couple, half-demented by the mysterious signal, who robotically go through the motions of preparing a party. Anna (Cheri Christian) decorates with balloons and streamers, unable to comprehend that her guests are slaughtering one another just outside her window. Horndog guest Clark (Scott Poythress) also fails to register that anything is amiss, maintaining a laserlike focus on getting lucky. Bush's contribution is awkwardly out of sync with what went before, labored sub-"Shaun of the Dead" silliness.

The conclusion only partly succeeds in winching the story out of the ditch. Gentry re-establishes the focus on Mya's run to safety, with Ben and Lewis on her heels. It's a generic exercise in chase-scene tension. With just one compelling sequence emerging from so many filmmakers' efforts, "The Signal" is decidedly less than the sum of its parts.

Colin Covert • 612-673-7186