When The Virgin Wolves perform, the girls in the band have a certain look on their faces — smiles they try to mask.

Vocalist Jaimeson Robbins and bassist Kristin Leigh both tend to sport a slick, mischievous expression that says, “I can’t believe we got away with this” — like kids that pulled a major prank in the neighborhood and didn’t get caught.

That expression seems incongruous considering just how mean and nasty their blues-rooted, devious garage rock can be. Maybe that’s why the girls try hard not to let those smiles shine through.

Honestly, if you close your eyes and listen to Pretty Evil Thing (not the Denton-born band’s first release but certainly the sharpest knife in their drawer and the first full-length LP), the last thing you hear is joy. You hear pissed off. You hear snarl and, at times, moments of spitfire and raw aggression.

This is no blues band, mind you. But unlike so many colleagues, they don’t hesitate to acknowledge the genre as the concrete of their sound, a foundation that’s buried in muck and broken glass of ’70s hard rock and clearly interred in the dirt and mud of the Delta blues.

The Virgin Wolves is a rock-and-roll band in the truest sense. One that sounds mean, and one you expect to be mean in concert. But what you get instead is a group of musicians having such a great time, obviously so in love with their new batch of songs that they can barely contain their joy.

It’s a disorienting combination of emotions for a rock show of this nature — but it works.

Pretty Evil Thing opens tough, with the fast, impatient “Black Sheep.” (Their first single precedes the LP’s December 21 release with a whip-snotty music video.) That’s followed by the hollow, reckless, bonk drums of “Crawl” and the slow, murky, blues slurp in the verses of “End of the Line,” that's countered with a crashing bi-polarized chorus, showing their gift for dramatic, contrasting and moody dynamics.

There are no flashy solos or over-the-top, rock radio vocal acrobatics, despite Robbins’ clear range for such. The drums and guitar work is all feel — unclean, yet you want to risk infection just to taste more. At times, the simple yet unique rock riffs echo the creep-a-billy resin of The Cramps (“Same Familiar”) and, at others, the sound of mucky Louisiana swamp blues (“Lies”).

Then there’s the reckless and destructive guitar and drum bounce of “Crooked Smile” and a clear highlight on the album in “Oh, Sugar,” with its big boom of Black Sabbath in the beginning and a slow, prog-ish excursion in the middle.

These rock songs can only be made with a lot of heart and zero expectations — with no commercial pressure to write something with mass appeal. Instead, The Virgin Wolves cut new paths in a familiar jungle of rock genres that call to mind everything from Blue Cheer to Fu Manchu, from the black-magic backdrop of Screamin’ Jay Hawkins to the big, round doom sounds of Wolfmother.

But the real treat is witnessing the show, because it’s all smash-the-TV mood music unleashed by a unique combo platter of personalities who can’t help but have the time of their lives playing it for you.

That makes for a rock show that you don’t tend to forget and would be happy to plunk down the change to see again, if only to look cool in front of a new friend you brought to the club.

Good news is you’ll get that chance December 21 at Hailey’s in Denton and December 31 at Wit’s End (formerly The Bone) in Deep Ellum.