The first 30 minutes or so of this picture are queasy for several reasons. After announcing itself as based on true events, “Sound of Freedom” depicts its hero, the Homeland Security agent Tim Ballard, apprehending a pedophile. Another agent, discussing their line of work and musing that “it’s a messed up world,” wonders why they’re not rescuing the children peddled by traffickers. Ballard, played by Jim Caviezel, gets a notion. He coddles the pedophile and sets up a sting. This nets him just one child.

The queasiness derives from the contemporary-thriller vibes of the police procedural material. They feel inappropriate. Then there are the scenes in which actual child actors perform being prepped for provocative pictures by adult groomers. What are the ethics of depiction here? The makers of this film initially seem to be grappling with how to properly tell this story. (It should be noted that the real-life Ballard has been accused of exaggerating his rescue narratives.)

“Sound of Freedom” settles on a tone of piety. Bill Camp as a sinner turned Samaritan (he gives the film’s best performance) relays his conversion moment to Ballard: “When God tells you what to do, you cannot hesitate.” As Ballard’s sense of mission grows, Caviezel is increasingly bathed in saintly light. “God’s children are not for sale,” he intones. In Colombia, he arranges a bigger sting, and after that, the narrative diffuses into an improbable “Heart of Darkness” style river journey. Only kind of dull.