Despite Samuel L. Jackson, this 'Shaft' is down for the count

Samuel L. Jackson as uncompromising private eye John Shaft hasn't lost a step, but the same can't be said of the latest iteration of the venerable franchise he stars in.

That would be “Shaft,” the ongoing exploits of the Harlem-based detective described as “Hotter Than Bond, Cooler Than Bullitt” when Richard Roundtree created the role in 1971 in a film that was a cornerstone of the action-heavy blaxploitation movement.

Roundtree took the character through two sequels before Jackson inherited the floor-length leather duster and the “I am the law” attitude in the 2000 reboot, also called “Shaft.” It still sounds good to hear the man say, “I might take you down but I won't let you down.”

Now, 19 years later, there is yet a third film titled “Shaft,” one that stars Jackson, seeks to pay tribute to Roundtree and hopes to pass the duster to a third-generation shamus, JJ or John Shaft Jr., played by Jessie T. Usher.

That would be a tall order for any film, but for this negligible, haphazard venture, directed by Tim Story and written by Kenya Barris and Alex Barnow, it just is not in the cards.

Jackson is so energized and brings so much skill and charismatic pizzazz to the role that it's hard to believe he is 70 years old. Or that the still-cool Roundtree, upgraded here from the uncle to the father of Jackson's character, is actually 76.

The problem with the new film is twofold, the start being that Jackson's Shaft is presented as a man blithely unchanged by the passage of time.

Like it or not, he's the same proudly profane and unapologetically politically incorrect operative whose arrogant attitudes toward women and others have not budged an inch. This may be defensible in theory but it is difficult to sit through in practice.

Also unfortunately, perhaps because it has to find things to do for three generations of folks, this latest “Shaft” has a too-busy plot, a story line stuffed with so many complications it can be hard to figure out what is going on.

Things start simply enough, with a flashback to 1989 and a car parked on a Harlem street. Inside are Jackson's Shaft and the woman in his life, Maya Babanikos (the always deft Regina Hall), who is reading the detective the riot act about the reckless, feckless way he lives his life.

Shaft, for his part, is only half listening to the lecture; he is noticing that an attack on his life is about to begin. Though surviving it is no problem - no matter how many bullets are sent in his direction, they almost always miss - Shaft's relationship with Maya is not so fortunate.

Furious that he has put their infant son in jeopardy, Maya gets out of town, and the only connection Shaft has with his son are the wildly inappropriate presents (condoms, anyone?) he sends as birthday or Christmas gifts.

Cut to 20-some years later, when son JJ, an MIT graduate, shows up in Manhattan as a data analyst for the FBI, an eager-for-action type constantly being lectured about knowing his place by his taciturn boss (a thankless role for Titus Welliver, so convincing as Amazon's “Bosch”).

Then Karim Hassan (Avan Jogia), one of JJ's closest friends since childhood, is found dead under suspicious circumstances that the police are all too willing to label a drug overdose.

Encouraged by Sasha Arias (Alexandra Shipp), yet another childhood chum who is now a New York doctor, JJ decides to investigate Karim's death, but a trip to Harlem to get information out of a drug dealer does not end well.

Which is how JJ comes to knock on the door of his father's office in the Amsterdam News building (dad turns out to still read the print edition) and ask for his help. Shaft senior agrees to provide it, but he's got an agenda of his own.

“Shaft” is light on its feet at times, with Jackson in character joking about being confused with Laurence Fishburne, and the film does get some entertainment out of the odd-couple father-and-son bickering.

JJ, for instance, lambasts his dad for committing “human rights violations” and the senior Shaft complains about his son's taste for exposed brick and coconut water.

But finally the plotting is so leaden and the fire fights so pro forma that not even the sight of the three Shafts in action can keep this film from sinking under its own weight. Yes, the great Isaac Hayes music makes an appearance, but the old days are gone and they are not coming back.