I’m supposed to be writing a review for "Snitch," the latest action thriller starring Dwayne "The Rock" Johnson, but there’s only one thing on my mind: a beard.

The tuft of hair belongs to Barry Pepper's chin, and it is admittedly mesmerizing. It’s a grungy-looking goatee that hangs two or three inches off Pepper’s face and sharpens into a point. Every camera angle provides some new fascinating detail, and even when it seems the beard has worn out its welcome, Pepper ties it into a tight little ponytail for variety’s sake.

Pepper’s mangy Van Dyke beard would be more at home in something like "True Grit" or "The Road." I’m more than thankful, however, that writer/director Ric Roman Waugh thought it was necessary because it’s one of the only interesting things "Snitch" has to offer. Everything else is dull, drab and surprisingly preachy.

Johnson plays John Matthews, the ridiculously buff owner of a construction supply business and an all-around good guy. His fairly calm life takes a turn for the worse when his son Jason (Rafi Gavron) is mistakenly arrested in a drug sting with his friend’s drugs and faces at least 10 years in prison thanks to the mandatory minimum sentencing laws.

The police offer to shorten Jason’s sentence if he helps them set up and arrest another dealer, but since he’s not an actual dealer and not even really a user, he has no one to turn in. Plus, he doesn’t want to set up an innocent guy – like his friend did to him.

While Jason languishes in prison, Matthews volunteers to do the snitching in the place of his son. The election-minded U.S. Attorney (Susan Sarandon) takes the deal, and Matthews plots to entrap a local dealer (Michael K. Williams, Omar from "The Wire") with the reluctant help of one of his ex-con workers (Joe Bernthal from "The Walking Dead").

The desperate dad’s plan might be too good, however, as he gets deep enough to start doing favors for a dangerous kingpin (Benjamin Bratt).

Much of "Snitch" plays as an indictment on the mandatory minimum laws and the sad realities of the country’s war on drugs. Every time we see Jason in prison – with increasing amounts of bruising – Antonio Pinto’s score hammers on the sad violins, most of the government officials are uncooperative or self-serving and there’s a good deal of dialogue dedicated to the injustice of Jason’s sentencing.

I give Waugh and his co-writer Justin Haythe credit for attempting to give some weight to what appears to be a generic thriller, but the film is more noble than successful. The script simplifies the complicated mandatory minimum discussion into an unfortunately preachy sermon. A better look into the topic can be found in Eugene Jarecki’s documentary "The House I Live In."

When it comes to the plot, the dialogue doesn’t fare much better. It isn’t offensively bad – maybe a bit reliant on clichés ­– but it’s lethally dull. There’s no color or character to the conversations, which instead just drably move "Snitch" from scene to scene.

Waugh’s pacing aims for procedural drama, but it collides uncomfortably with the movie’s Hollywoodization. I love Dwayne Johnson – he has the charisma of Schwarzenegger combined with a touch of genuine acting talent – but his role here isn’t right for the former wrestling star. It’s hard to be convinced he’s a vulnerable everyman in a realistic drama when his physicality and presence lords over every other character on screen. Bratt’s drug lord isn’t much of a threat when Johnson looks like he could snap him in half without breaking a sweat.

That’s not to say Johnson turns in a bad performance in "Snitch." He’s technically fine, but it’s hard to find his effortless charisma underneath the character’s blandness and the film’s preachy importance. No one else in the cast fares much better except for Williams, who brings a slithery menace that reminds viewers why their friends keep pestering them to watch "The Wire."

Since it is a Johnson vehicle, there must inevitably be some action, too. Unfortunately, it doesn’t happen until the last act and plays rather limply. Waugh is a believer in shaky cam, which makes the end freeway chase a typical mess of edits.

Worst of all, the action sequences feel entirely out of place with the rest of the film. It’s a silly shift from serious realistic drama to dumb overblown blow-‘em-up that fits as smoothly as a musical number at the end of "Zero Dark Thirty." A scene involving Johnson standing in front of rows of guns is one of the movie’s biggest laughs, just because it’s the official moment "Snitch" kisses reality goodbye and sets sail aboard the S.S. Ridiculous.

The film doesn’t appear to have the confidence or conviction to follow through on its "true story" and instead goes for action movie heroics and a Hollywood ending.

Then again, the writers’ conviction to the overall true story (originally reported by "Frontline") is pretty weak. James Settembrino is the real-life father, and his attempt to get his entrapped son out of prison featured no flipped semis. Settembrino had a drug bust set up with the government, but the arrangement fell through, and his son still served the time. So only about 15 minutes of "Snitch" is based on reality; the other 97 minutes are purely hypothetical.

I’d like to think Barry Pepper’s beard was real though.