"Saw III" makes a convincing case that this surprisingly popular and hugely profitable horror series should stop as a trilogy. This is not because the quality of the films have decreased over time. Quite the contrary, "Saw III" is easily the best of the bunch, just as 2005's "Saw II" was a step above 2004's original "Saw." Instead, the trio of movies as they now stand form a complete whole, with all of the principal characters of the series dealt with and their arcs completed, and all of the plot holes and most of the unanswered questions of the previous pictures now satisfactorily filled in. The only possible reason for a "Saw IV" would be purely and distastefully monetary. Lions Gate execs, take note: the story is now finished; don't strain things out for a quick buck and at the expense of a franchise as oddly noble as it is grisly.

At the conclusion of "Saw II," it was revealed that Amanda (Shawnee Smith), the only known past survivor of the cancer-afflicted Jigsaw's (Tobin Bell) sick games, was now his willing apprentice and the likely successor to his maniacal methods. Set not long after the previous film, "Saw III" picks up with Jigsaw and Amanda kidnapping skilled but emotionally frigid doctor Lynn (Bahar Soomekh). Trapped in a head device that will blow her brains out the second she tries to escape or the dying Jigsaw's heart stops beating, it is up to Lynn to keep him alive. Her only chance to be set free lies in the unknowing hands of Jeff (Angus Macfadyen), a grieving father who has not been able to get over the death of his son. Secluded in a different part of the abandoned warehouse/torture chamber, Jeff is forced into a series of games that will put him face to face with people connected to his child's accident and test not only his will to live, but his ability to let go and forgive those he believe have done him wrong. If Jeff passes, he and Lynn will be allowed to walk.

Directed by "Saw II" filmmaker Darren Lynn Bousman, "Saw III" is an exercise in nihilism so violent, so gruesome and so wince-inducing that it literally makes its predecessors look like leisurely strolls through Central Park. As if the bar could be raised any higher following the likes of 2006's blood-drenched "The Hills Have Eyes" and "Hostel," the film sets a new standard for what can be graphically depicted in an R-rated horror movie, all the while revealing the hypocrisy of the MPAA ratings board when it comes to their leniency on violence and their puritanical stance on sexual content and nudity. "Saw III" is unremittingly grim and gory and visually frightening, but the onscreen suffering and torment would be nothing if there wasn't an actual story to be told. This is where the film excels beyond the first two series entries, because it must introduce and develop a new premise while building upon, deepening and wrapping up the previous ones. Now a complete trilogy, the series looks much better in hindsight and is also quite impressive for having been conceived so seamlessly in the span of only two years.

Written once more by Leigh Whannell, the script of "Saw III" is the tautest one, doing away with the police procedural subplots that bogged down the other two films and centering on the breathlessly riveting dual—but connected—tales of entrapped protagonists Lynn and Jeff. Lynn, played in a sympathetic performance by Bahar Soomekh (2005's "Crash") that demands both pure terror and coolheaded proficiency within the same breath, is used as a means to exploring the psyches of Jigsaw and Amanda and their close, if dysfunctional, relationship with each other. Now on his deathbed, Jigsaw refuses to give up without a fight even as he has elected Amanda as his valued assistant to the mayhem he very much still wishes to wreak on those he believe are morally corrupt or unappreciative of their lives. In return, Amanda can't help but grapple with the option of playing by his rules and making her own now that she thinks, perhaps hastily, that she has the upper hand over the ailing Jigsaw.

As Jigsaw, Tobin Bell by now is effortless in his transformation as one of the most indelible screen villains of the twenty-first century, his calm and collected demeanor all the more chilling in the face of the living nightmares he has masterminded. Brief glimpses into his past help to round him out further as a psychotic but purpose-driven man instead of just a plain, old monster. Meanwhile, Amanda is not penned by Whannell or portrayed by Shawnee Smith (2004's "A Slipping-Down Life") as an unfeeling ice queen, but a complex woman confused about her purpose in life and unable to cope with the events that have led her to the present. She's still very much a "bad guy," but she's a "bad guy" with more humanistic facets than the norm. Of the four central players, Angus Macfadyen (2002's "Divine Secrets of the Ya-Ya Sisterhood") is on a lesser plane as Jeff, although part of that may be attributed to the stilted dialogue he is forced to utter as he decides whether or not to save the lives of those he has sought to pay vengeance toward. Nevertheless, Jeff's subplot as he travels from room to room and deadly game to deadly game, confronting his demons in the process, is equally gripping to Lynn's and nearly as suspenseful.

In keeping with tradition, "Saw III" ends with one revelation built atop another. They are less shocking and unanticipated than the earlier films, and yet are more cohesive and play fair with the audience. Cameos from the severed sow's head and the painted-faced puppet also make welcome appearances, the latter because its origin is finally revealed and is used in a way that makes it more than a cheap gimmick. If a misstep occurs during the tense final moments, it is in the obvious and almost clumsy way the twists are explained. Is it really necessary to flash back to a moment that has occurred only thirty seconds earlier when any audience member with half a brain would have understood without the details spelled out for them? This debit and the occasional awkward line of dialogue besides, "Saw III" is really quite a nifty and superb thriller that surpasses the expectations of a project rushed so quickly into production. Coming only a year after the last series effort, "Saw III" has been seemingly thought out with precision and executed with irresistible macabre flair. It's an ideal and superior capper on a trilogy that should stay as just that.