Mud sees writer-director Jeff Nichols straining to straddle two disparate sets of genre requirements: those of the magical-realist backwoods fable and the soppy heartland melodrama. Its closest relatives are Charles Laughton's The Night of the Hunter and Elia Kazan's Wild River, but shot through with the "gritty" vision of cruddy home life and bayou listlessness of Lance Hammer's Ballast. Matthew McConaughey's eponymous character, a starry-eyed river urchin hiding out from a crime of passion on a small island in Arkansas, is discovered by young friends Neckbone (Jacob Lofland) and Ellis (Tye Sheridan). Dragging from a seemingly bottomless box of cigarettes, Mud wears a single too-clean white shirt throughout, and like the film, he embodies an odd mix of the lofty and lowbrow, the allegorical and quotidian.
Given his piss-poor situation at home (his father's fishing "business" nets a few hundred bucks a week, and his parents' marriage is crumbling accordingly), Ellis, nicknamed "Guts," is drawn immediately to Mud. City officials deem the riverbank community unsuitable to live, and so while riding shotgun on a weekend fish sale, Ellis's father tells the 14-year-old that "this way of life ain't long for this world" and "you can't trust love, Guts; you're not careful, it'll up and run out on you." Sam Shepard brings further portent as Mud's only real friend, an ex-CIA codger who stands on his riverside deck and watches the boys through binoculars, and soon it's revealed that Mud is hiding out after killing a man—a "bad piece of business"—who impregnated and then mercilessly beat the love of Mud's life, Juniper (Reese Witherspoon).
Mud is pretty much a real-life angel with a dirty face and filth-speckled washboard abs, befriending the two teens with a can-do attitude and know-how on getting an abandoned boat—his temporary home—out of a tree and back onto the Mississippi. Portraying a heartsick man of immense charm and genuine demeanor, McConaughey gives unexpected shades to his antihero as the help the hermit asks of Neckbone and Ellis grows more intense. The tantalizing possibility that Mud is a litmus test for the boys' judgment is mostly left aside, but neither does Nichols indulge the inevitable expectation that he's going to teach them a Very Valuable Lesson. While the boys begin ferrying messages to Juniper in a two-bit motel, a coterie of slick-haired men with guns arrive in town concurrently, on the hunt for Mud. Their employer is a withered evangelical Christian businessman (Joe Don Baker, adding serious tonnage to a character with about five lines of dialogue) whose son was the man killed by Mud.
While Ellis falls in love for the first time, Nichols struggles visibly to keep Neckbone in place as more than just a best-friend character. Neckbone looks the other way as his caretaker-uncle, Galen (Michael Shannon), boozes and sleeps his way to some actual words of wisdom as the gap between the man and the kid widens visibly. Though Shannon brings some comedy to a self-serious mix, his character is nevertheless extraneous; the plotline's forward momentum reacts badly with Nichols's desire to make a breezy, shaggy-dog story. But Juniper's inability to commit to Mud adds a layer of complication to Ellis's motivation for helping Mud, and the film deftly illustrates the disjunction between hope and pessimism—and the kinds of stories people tell themselves out of uncertainty, how they cope (or don't) when things don't pan out. The film makes obvious that the journey from childhood to manhood is shared by the two boys from its first scenes, where they sneak out before the day starts to speedboat through the delta, but it's also, in some ways, shared with Mud.
Ellis doesn't just lose his innocence; by helping Mud, he trades it for disillusionment, only to reconcile his herky-jerky emotions only part way by story's end. Despite its overstuffedness of plot and character, Mud ultimately succeeds thanks to small details, from its deep-fried lingo and the swampy texture of its location photography to its uniformly expert cast. The real knockout is Sheridan, whose pubescent Charles Bronson-esque demeanor is instantly winning and ultimately used to moving effect. After getting his heart broken, Ellis tearfully calls Mud out for playing the boys to his advantage—a penultimate showdown that, if ham-handed on paper, comes off fluid and inarguable on screen. The next beat gives Mud a chance to redeem himself in total, a miraculous consequence of plot-gerrymandering, but who cares? Nichols's hand is so sure at making the ludicrous feel immediate, it's hard to notice before the movie is over.