A middling thriller wrapped around a compelling lecture about the child sex trade in Southeast Asia, “Trade of Innocents” gives us a peek at a sordid underworld, but a full view of the conditions that feed it.

“Inspired by real events,” it features Dermot Mulroney and Oscar winner Mira Sorvino as an American couple in Cambodia to do something about the burgeoning traffic in children sold into prostitution.

Mulroney is Alex, ex-military, a man with a mission — freeing children, capturing the Khmer traffickers and Vietnamese pimps who sell them and exposing the Western perverts who travel to that part of the world to pursue the “freshly picked flowers” of Asian girlhood.

He and his wife Claire have taken on this mission because of tragedy in their own lives. And their paths — Alex heads a team, working with government officials, in this crackdown — have them on a collision course with both the pimp who calls himself “The Duke” (Trieu Tran) and a little American-born girl who will, we’re sure, soon be in The Duke’s sights.

In classic melodrama fashion, events are set in motion by a sweaty American pedophile (John Billingsley), a supposed “family man” who uses his long stays in the Orient to fulfill a perverse lust.

“I said YOUNG girls,” he hisses to The Duke whenever anyone over the age of seven is paraded before him. His haggling over price, over “requirements” is easily the most disturbing thing in writer-director Christopher Bessette’s film.

Alex lectures the Cambodian authorities about this problem, stopping only to hear their complaints that culture and custom require children to be of financial use to their parents, that rural parts of the country (and Vietnamese refugee camps) are rife with this trade because families would rather sell one child than see all the rest starve. Mulroney, stolid and solid as ever, listens and ignores these protests. He’s on task.

Sorvino’s Claire is forever on the verge of tears, both from memory of her own loss and the horrors facing these children in the Third World.

The movie’s tone is rightfully serious, downright overwrought, at times. Girls who have escaped the trade tell their stories to Claire, who weeps. Sorvino gives Claire a grieving heart and a steely spine.

But when Mr. Pervert drags a child he has rented for a month to a bar and requests that the band play “Puppy Love,” the only proper response is guilty laughter. The sick becomes the silly. And when Alex interrupts a chase to harangue a DVD pirate that the same organized crime that his business supports is responsible for child sex slavery, involuntary eyerolls follow.

MPAA Rating: PG-13 for disturbing thematic material involving sex trafficking of children, and some violence

Cast: Dermot Mulroney, Mira Sorvino, John Billingsley, Trieu Tran

Credits: Written and directed by Christopher Bessette. A Monterey Media release. 

Running time: 1:30