Despite the roots of the new NBC series “The Firm,” based on John Grisham’s 1991 best-selling novel, it’s not solely a legal show. Nor is it exactly a procedural, a mystery or a character drama. A mix of all those elements exists within the series, which will either add intriguing layers as the show continues or be its ultimate downfall as it spins in too many directions.

The two-hour pilot debuting tonight is strong and goes in every direction tantalizingly. Enough happens to keep you from changing the channel, but there are hints of a show that could get dull fast.

The show picks up 10 years after the book (and 1993 film adaptation starring Tom Cruise), which wrapped up as fearless lawyer Mitch McDeere sold out his mafia-owned law firm to the feds to get out alive. Mitch rejected witness protection, and the mob put out a hit on his family. To protect them (and his newly pregnant wife), the McDeeres went undercover.

Now, Mitch (Josh Lucas, of 2002 rom-com “Sweet Home Alabama” fame) has decided that it’s time to reclaim the family name. The McDeeres live happily in suburban Washington (filmed in Toronto, although the opening scene shows Mitch sprinting down the real-life steps of the Lincoln Memorial). Mitch works at his own one-man law practice and spends mornings making pancakes for his 10-year-old daughter while his doting wife, Abby (Molly Parker), teaches elementary school.

It’s all very idyllic, unless you count the creep in the car across the street snapping photos. Newsflash: The mafia never forgets. Somehow, Mitch missed that memo in law school or has never seen a mob movie.

It also could be that he’s breathtakingly dumb. This leads to one of the few glaring problems in the pilot, which is that while Lucas looks the part described in the book of the handsome, brilliant lawyer, Mitch is the least compelling character on the show. Not only does he make questionable decisions, but he’s a walking contradiction. One minute he’s a shark contemplating tearing apart a 14-year-old witness on the stand; the next he’s an everyman with a heart of gold helping a grieving father; and the next, he’s completely ego-driven as he considers partnering with a big firm when his small practice is struggling to make ends meet.

“I’m the son of a coal miner and a waitress, not a bank president and a socialite like you,” he says wistfully to his wife, delivering a monologue about how unfair it was that a Harvard graduate like himself had big dreams that were unfairly ripped from his grasp after that whole “the mafia secretly owned my law firm” debacle.

Since Mitch is the central character, this is troubling, but he’s surrounded by a surprisingly dynamic supporting cast. Readers of the original will recognize names, such as Mitch’s grizzled ex-con brother, Ray (Callum Keith Rennie), who brings a comedic element with decent one-liners. Ray has since shacked up with Tammy (Juliette Lewis), the sultry receptionist Mitch hired to help bring down the original firm, and he is now a private investigator for Mitch’s law practice. He also drives Tammy crazy by refusing to put a ring on her finger.

Also stealing scenes is Tricia Helfer, who plays Alex Clark, a law firm managing partner with supermodel looks who says things like, “I find facts often get in the way of a perfectly winning argument” and vaguely threatens Mitch’s wife by simply existing. Her practice, Kinross & Clark, tries to hire Mitch as another partner. On paper, it’s because Mitch has impressed them with his legal work – but, naturally, this leads to a twist that sets up the season.

Deftly navigating among the upcoming situation with his new firm (which inherits Mitch’s ragtag team), the caseload at Mitch’s practice, the family dynamics and, oh yeah, the mob issue that refuses to go away, the pilot sets up many possibly intriguing situations for the future while not taking itself too seriously.

“We were a little scarred by our last firm experience,” Mitch jokes as he and Abby get a tour of Kinross & Clark, driving it home again that he’s not put off by a little mafia scare.

There’s a lot going on, but for now, “The Firm” seems intriguing enough to have the time to decide what it wants to be.