"The Guilty," an effective police thriller in which an emergency dispatcher gets ensnared in a messy abduction case, plays out entirely within the cramped offices where the calls come in, and we never see some of the crucial characters — we only hear them over the phone. But this well-paced Danish film is never boring: It uses sound brilliantly, radiates with tension and offers its share of crafty twists.

Asger (a flawless Jakob Cedergren) is not exactly the guy you would want on the other line if you dialed 911. He upbraids callers for what he considers their questionable behavior, and one could get better emergency service from a recording. It's clear that Asger doesn't want to be at his workplace, and soon, we discover that his dispatch assignment is not of his own accord.

But a routine night at the emergency center suddenly turns upside down when Asger gets a jumbled but urgent phone call from the trembling Iben (Jessica Dinnage, excellent in a vocal-only role), who reports that her unstable ex-husband has forced her into a van and separated her from her young children. To Asger, the kidnapping is a matter of life and death, and his investigative instincts go into overdrive for a domestic case that will turn chillingly violent.

Director Gustav Moller is skillful at meting out the plot turns, but he's got more on his mind than making a competent police procedural. "The Guilty" is also a formidable character study, and bit by bit, we figure out that Asger has some serious troubles of his own — troubles that will affect how he handles the emergency and how he will move forward from his life-changing night. This film lives or dies on the central performance, and Cedergren, shot extensively in close-up, pulls off the role admirably.

Though the ending is slightly anticlimactic — mainly because the twists beforehand have been so memorable — "The Guilty" provides a master class in low-budget yet high-concept independent filmmaking. It's riveting.