One could spend a great deal of time complaining about how implausible the premise behind “Saw IV”—that puzzle killer John “Jigsaw” Kramer (Tobin Bell) reaches out from the grave to continue his slaughter spree—is. But that would be missing the point. The “Saw” series has been absurd since the initial episode, a ludicrously convoluted (as well as goofily gory) tale of a dying man using death-threatening contrivances to force bad people to confront the reality of their lives, or die instead. But as silly as it was, the original picture had some over-the-top cleverness to it. It was nonsensical—and one must hasten to add, visually disgusting—but at least it had some imagination, and structural skill, to it.

That’s what’s been lacking in the triad of sequels, most notably this latest entry in the series. Not that scripters Patrick Melton and Marcus Dunstan haven’t crafted something complicated. But none of it hangs together: the narrative is so complex that it’s virtually impossible to discern, from any logical perspective, what’s going on from moment to moment. (I defy anybody who hasn’t committed the previous three pictures to memory to explain what’s happening in the last ten minutes.) And imagination without any controlling idea simply makes for a mess, which is what “Saw IV” is. And an ugly mess at that.

It opens with a revoltingly detailed autopsy on Jigsaw’s corpse, which reveals an audio tape within his stomach that informs Detective Hoffman (Costas Mandylor) that the madman’s game is continuing. That morphs into a challenge to another of the cops from previous installments, Rigg (Lyriq Bent) to engage in a wild chase to find people encased in typically Rube Goldberg traps, the last two of whom are none other than a bound Hoffman and the long-missing and about-to-be-hanged partner of Rigg, Detective Matthews (Donnie Wahlberg). Interspersed with his pursuit are scenes involving a couple of special agents, Strahm (Scott Patterson) and Perez (Athena Karkanis), who follow his trail. And they in turn bring in Jigsaw’s widow Jill (Betsy Russell) in for questioning—which allows for ample flashbacks about the dead killer’s past (giving Bell the opportunity to rise from the dead, as it were, and the scripters the chance to explain his switch to the dark side in a particularly humdrum plot turn). It also introduces yet another character, Jigsaw’s lawyer Art Blanc (Justin Louis), to the mix.

Everything does hang together to some degree, but the hows and whys are approximate at best, and it doesn’t help that the makers keep dropping in frames from earlier installments in the series to “explain” the connections—a tactic that won’t be terribly successful even for fans, especially toward the close, where the chronology seems to go entirely awry. And the “lesson” taught to Detective Rigg is about as ridiculous as they come, hardly worth even a dead man’s effort to teach. The narrative murkiness is accentuated by the gloomy cinematography by David A. Armstrong, which keeps the visuals so dank that it’s often hard to distinguish what’s going on, and particularly by the drunkenly abrupt editing of Kevin Greufert, which makes the “action” sequences so woozy that they actually have a nauseating effect.

Add to the mix Darren Lynn Bousman’s flat direction, piles of fake gore and terrible acting across the board—Bell was actually more expressive when he was wearing that mask—and you get a very unsavory brew indeed. If it ever had a prime, the “Saw” franchise is well past it, and with the recent decline of interest in the whole torture porn genre, this dull blade may bring it to a close. It’s about time.