“I Am All Girls” is a melodramatic South African thriller about the international sex slave trade, with hints at its vast reach and its long sordid history and a suggestion that the only “solution” to it is avenging, in-the-know cops.

Which is to say, it starts off with pathos, heart and purpose, and kind of devolves into derring do and shootouts. Kind of frustrating that way, really.

It’s “inspired by” a true story, although its historical background isn’t easily ascertained on the Internet. In 1994, a child trafficker confessed, fingered higher ups in the Apartheid government, and did all this on tape, only to wound up dead in his cell the next day.

This was all covered up by the corrupt, racist regime of the day.

“All the Girls” is about that story, and its present-day blowback. As it flashes back and forth in time, freeze-frames show us photos of missing girls, black and white, from South Africa.

Somebody in the present day has access to that long suppressed video confession. Somebody is watching it, tracking police investigations and showing up ahead of the cops, or getting the “justice” that the “system” isn’t — shooting offenders, past and present, and carving initials in their chest.

Erica Wessels plays Det. Jodie Snyman, the archetypical “cop who cares too much.” She’s getting ahead of herself, making mistakes, failing to get convictions.

Because she weeps when she raids a brothel or busts open shipping containers filled with kidnapped girls bound for the Middle East.

She’s constantly lectured about by her captain (Mothusi Magano), who takes her off her Hawks (Directorate for Priority Crime Investigation, DPCI) team and pushes her onto a simple murder case just to get her to “take a break.”

Only her colleague, the quietly intense Ntombi (Hlubi Mboya) understands. These two have history and/or chemistry. Too bad special police like this aren’t supposed to know where each other live.

Jodie’s new case connects to her old case, the bodies pile up and little girls, then and now, go through the hell of abduction, transport and sex slave lives — murdered when they’re “used up” — in scenes that cut back and forth between 1994 and today.

Because the person doing the executing has a connection to that past, and no, that isn’t made a a secret here.

Donovan Marsh’s film bounces from Johannesburg to the port city of Durban, chasing shipping containers and those who fill them with children and ship them abroad.

Yes, shipping manifests play into the case, and yes, we see just enough of this from the victims’ point of view to be moved. Just not as much as you’d expect.

Wessels is pretty good at playing a drink-to-forget cop-movie archetype, Mboya’s role is under-developed, and the villains mostly faceless and certainly no one the film focuses on, any more than the faceless, mostly-nameless “girls.”

The most chilling scenes are the grainy video from 1994, a kidnapper (J.P. du Plessis) spilling the beans, naming names, suggesting that the worldwide traffic in children for rich and powerful pedophiles is indeed everything recent news reports says it is.

Giving up on maintaining the story’s mystery might seems like a cop out, and “I Am All Girls” gains nothing, dramatically, from this early revelation.

The structure is ad hoc and the plot choppy, with the action beats — such as they are — holding the movie together and maintaining our interest. But just barely.

MPA Rating: TV-MA, violence, sex trafficking subject matter, profanity

Cast:  Erica Wessels, Hlubi Mboya, Mothusi Magano, J.P. du Plessis and Brendon Daniels.

Credits: Directed by Donovan Marsh, script by Wayne Fitzjohn, Emile Leuvennink, Marcell Greeff A Netflix release.

Running time: 1:47