Two 14-year-olds, best friends living on the Mississippi River's Arkansas Delta, sneak off to a small island, where one of the kids, Neckbone (Jacob Lofland), has discovered something strange: They pull up on the sand, hike through the woods, and there, lodged high in a tree, is an old boat. An epic flood must have left it there, and Ellis (Tye Sheridan) is surprised, and thrilled. A treehouse with a hull! The boys have a secret getaway that'll be theirs alone.
Not so fast. Someone's been living in the boat's cabin. And that someone turns out to be a fugitive.
So begins Jeff Nichols' Mud, a magical, scary, downright remarkable film. Echoing The Adventures of Huckleberry Finn, but also evoking the predatory menace of The Night of the Hunter and other books and films (To Kill a Mockingbird comes to mind) where children become immersed in an adult and dangerous world, Mud finds Matthew McConaughey at the top of his game. The actor, swimming boldly out of the mainstream lately (Killer Joe and The Paperboy), has the title role - a wiry figure with a giant water moccasin tattoo running down his arm, and a giant longing in his heart. He's killed a man out of love, and now he's come back to where he grew up to reclaim the girl of his dreams and run away together.
That's the story, anyhow, that Mud tells Ellis, as the mystery man with the gun tucked in his pants, smoking cigarettes and ruminating about fortune and fate, befriends the wide-eyed youth.
"He's not dangerous," Ellis insists to Neckbone after they've gone on a couple of stealth missions for Mud. And after they've seen the roadblocks and the wanted posters around town.
"Sounds like a whole lot of state troopers think different," Neckbone says.
Mud is the third feature from Nichols, an Arkansas native whose Shotgun Stories (2007) felt like back-country Greek tragedy, and whose Take Shelter (2011), with Michael Shannon as a family man haunted by nightmare visions, channeled so much angst you left the theater shaking.
Mud, similarly, is set in a world of absolute authenticity. Ellis lives on a houseboat, where his parents' marriage is coming apart (Sarah Paulson and Ray McKinnon radiate anger and regret). Neckbone lives with his river-diver father (Shannon, in an extended cameo). Sam Shepard turns up as a grizzled recluse who does a lot of peering through his binoculars.
And then there's Reese Witherspoon, who sashays into town in her platform shoes and cutoff jeans. She's Juniper, Mud's muse, the woman who's made him mad with jealousy and heartache. All he wants is to be with her, and it's not exactly clear what she wants - she's almost oblivious to the deadly commotion she's been stirring.
Though McConaughey is great - cagey, seductive, spooky, fierce - the movie belongs to Sheridan. Mud is Ellis' story, about a boy confused by what love is. His parents' love is disappearing before his eyes, and Mud's love for Juniper seems all-consuming, while Ellis finds himself smitten with a high school girl (Bonnie Sturdivant), and wants her desperately to be his. Sheridan, who played one of Brad Pitt and Jessica Chastain's sons in The Tree of Life, lives and breathes Ellis. His performance doesn't feel like a performance at all.
With its river rats and snakes (both human and animal), its Piggly Wiggly grocery and '60s-era motel - a motel that becomes the site of considerable danger - Mud is steeped in a sense of place, and the people inhabiting it. Southern. Superstitious. Suspenseful. Sublime.
Contact Steven Rea at 215-854-5629, firstname.lastname@example.org, or follow on Twitter @Steven_Rea. Read his blog, "On Movies Online," at www.philly.com/onmovies