It has been almost eight years since Mel Gibson last headlined a film (2002's "Signs")—in the interim, he has become better known as a punchline for his well-publicized personal and legal foibles—and the question on many people's minds is whether or not he still has leading-man potential and the ability to still open a film. Moreover, will audiences be able to separate knowledge of his real life with that of an onscreen fictional character? The answer to all these questions, as it turns out, is yes, and Gibson has picked just the right project to return to the spotlight. "Edge of Darkness" could have potentially been an old-hat tale of vigilante-style vengeance, but is lifted above the mundane by vivid performances, energetic direction by Martin Campbell (2006's "Casino Royale"), and a plot that works simultaneously as a taut action-thriller, an engrossing murder mystery, and an evocative statement on the dark side of big business and governmental politicking. Gibson is certainly in his element, adopting an authentic, unwavering Boston accent to play a man whose fragile emotional state is used to his advantage in getting back at the people responsible for taking away his very lifeblood.

24-year-old Emma (Bojana Novakovic) has no sooner returned to her Massachusetts hometown to visit her single father, homicide detective Thomas Craven (Mel Gibson), that she grows seriously ill and is subsequently brutally gunned down on their way to the hospital. The authorities and press presume that Thomas was the intended target, but he's not so sure about that when he discovers a gun hidden amongst her belongings. Desperate to get to the bottom of his only child's death, Thomas finds that Emma's respective boyfriend Burnham (Shawn Roberts) and coworker Melissa (Caterina Scorsone) are likewise fearing for their lives while sworn to keep quiet. His investigation ultimately leads him to Emma's place of employment, Northmoor Research Facility, and a deadly conspiracy that company head Jack Bennett (Danny Huston) seems to be behind.

Based on the 1985 BBC miniseries by Troy Kennedy Martin, "Edge of Darkness" has been handily adapted by screenwriters William Monahan (2008's "Body of Lies") and Andrew Bovell. A narrative device where Thomas hears his late daughter's voice and talks aloud back to her approaches silliness, but this is fortunately sparsely used. The rest of the picture works like gangbusters, keeping consistently engrossing as the viewer follows Thomas' investigation and fits together along with him the puzzle pieces that led to Emma's murder. Knowing as little as possible about the story's turns and revelations can only prove beneficial to one's involvement, clues popping up early on—three drowned bodies rising to the water's surface; Emma's mysterious sickness before her death—cleverly hinting at what is to come.

Necessary exposition and dialogue-centric scenes, deliciously penned and acted, between Thomas and the rest of the supporting players are typically just as riveting as the tense, veritably surprising set-pieces of threatening action and high-stakes confrontations. When the latter arrive, director Martin Campbell exudes the same coherent style and know-how that he brought to James Bond entry "Casino Royale," delivering high intensity, formidable stunts, and a gritty brutality that makes one feel every punch, gunshot, and car crash. The look and feel of the film's Boston setting, well-contrasted with the interludes set in the smaller New England towns scattered across Massachusetts, are always on-point, while the loss that Thomas still grieves over is invariably apparent in his eyes.

It is a credit to Mel Gibson that he is able to disappear into his character, sans the actor's baggage, while again portraying the kind of strong, tough, confident protagonist he is known for. His hair may be thinning and the lines across his face may be growing deeper, but Gibson's virility has never been more apparent. It would have been nice were Thomas' past better developed—it is never explained where Emma's mother is, or, for that matter, why Thomas doesn't seem to have any relatives at all—but this missing info is mostly made up for by the stark reality Gibson brings to his distressed character. Ray Winstone (2007's "Beowulf") is a standout as the elusive Jedburgh; where his allegiances lie is a big question kept open until the end, and Winstone straddles the line between jovial and threatening with masterful ease. In other memorable supporting turns, Danny Huston (2008's "How to Lose Friends & Alienate People"), as Jack Bennett, proves a terrific villain in his alternating smarmy bravado and terminal cowardice; Bojana Novakovic (2009's "Drag Me to Hell") makes an all-important impression with fleeting screen time as ill-fated daughter Emma; Damian Young (2009's "Everybody's Fine") depicts crooked Senator Jim Pine with a fitly enraging highfalutin smirk; and Caterina Scorsone, as the frightened Melissa, impresses in her wrenching face-to-face scene opposite Gibson.

Building momentum and laced with a series of socko, audience-pleasing climactic moments, "Edge of Darkness" delivers upon what it promises—and then some. Violence, unflinching without growing gratuitous, intermingles with a subtly mournful tone that views what should, in a perfect world, be people of nobility—nuclear researchers and engineers, senators, company CEOs—and, instead, only finds dishonesty, skewed intentions, and inhuman corruption. Even as the ending proves relatively unconventional for a studio-based thriller, the last scene is the film's most obvious misstep. Clumsily devised and dramatically drippy, this conclusion could have easily been tweaked and corrected with a less saccharine touch. Regardless, "Edge of Darkness" remains an uninhibited, solidly voracious effort, taking Thomas Craven to the point of no return and beyond. His actions might not always be right, but somehow they seem awfully just.