I finally caught up with “Prisoners,” a sleeper hit from last fall that I missed until now because I decided to see the excellent “Rush” on a given weekend instead of “Prisoners.” I made the right decision, then, as “Prisoners”--despite a promising first two acts--collapses completely upon itself in the third act under the weight of increasing implausibility.

Though populated with superb character actors like Terrence Howard, Viola Davis, Mario Bello, Paul Dano, and a virtually unrecognizable Melissa Leo, the film basically revolves around Hugh Jackman and Jake Gyllenhaal. Early in the movie, the daughters of Jackman-Bello and Howard-Davis are kidnapped, and Gyllenhaal is the detective leading the search--which first focuses on the seemingly-shady Paul Dano-character before devolving into a morass of incomprehensibility.

When the movie focuses on the search and the increasing desperation and heartache of the parents who have lost their children, it’s a taut thriller, elevated considerably by a grim sense of foreboding shot beautifully by the esteemed cinematographer Roger Deakins. But, in the third act, there’s a pointless digression steering you toward a different villain which adds nothing and only serves to lengthen an already long movie--it’s almost three hours--to a ponderous length. It’s also confusing and muddles the plot.

After the Dano character is released from police custody because Gyllenhaal says “he has the IQ of a 10-year-old,” and the police don’t believe he could perpetrate such a crime, Jackman remains unconvinced, and he kidnaps Dano to do a little enhanced interrogation on his own. As if the movie wasn’t already tough enough to watch--I don’t even have kids, and I was wrenched watching these disconsolate parents weep for their children--we then get to watch a man evidently with the IQ of a child get beaten within an inch of his life over nearly a week. Here, I was hoping the movie would make a statement about how torture is not, in fact, a good way to glean information from people, and it seemed to be going that way, only to eventually leave you neither convinced of torture’s virtues nor aghast at its horrors. Take a stand, one way or the other! Stop with the cryptic ambiguity, please.

“Prisoners” is grim, gruesome, unrelenting, and horrible to view, yet it provides no real answers for the questions it raises. That nonsense with the red herring I mentioned earlier certainly did the movie no favors, and, personally, I didn’t buy the rationale of the real villain for their crimes. Also, at the absolute end, we’re supposed to believe one of the main characters is still alive despite mortal injuries, and I didn’t find that credible, either.

Jackman is impressive, though, going from a devout believer to a torturing demon. I also think Gyllenhaal can be quite good when he’s not running around as the “Prince of Persia”--and he has been outstanding in terrific films like “Brokeback Mountain,” “October Sky,” “Zodiac,” and “Source Code”--but he makes some odd acting choices here, like his near constant blinking. What was that about?

My other problem--and I guess this is a pet issue of mine, as I’ve brought it up with other recent films--is why bring in a top-notch group of actors if you’re going to give them nothing to do? Howard is a welcome presence in any film, but here he’s a passive observer, basically just playing off Jackman’s madness. The same goes for Davis, who at least is granted one explosive scene with a chained Dano. And Dano, who just gives off a creepy vibe seemingly without trying, only says a handful of words and seems to serve the movie only to be beaten beyond recognition. Finally, Bello has shown real aplomb in amazing films like “The Cooler” and “A History of Violence,” but she spends nearly all of “Prisoners” as a drugged-up zombie. Again, if you’re going to bring in a quality cast, give them real characters to play--don’t just make them part of the scenery.

In the end, I was disappointed by “Prisoners,” because the first two acts really had me going, only for it all to come apart in the end. Still, with the harrowing Jackman performance and the spot-on work from Deakins, I’ll give it a 55/60 (above average/plus) on the 20-80 scouting scale--even if I was ultimately frustrated by it.

Ryan Anderson can be reached at randerson@stjamesnews.com and followed on Twitter @randerson_ryan