As with many stories about coming of age under harsh circumstances, a mighty river runs through the center of Jeff Nichols' Mud, a Southern-fried fable about two adolescent Arkansas boys whose childhoods are wrested from them. Yet unlike last year's excellent Beasts of the Southern Wild, this is a fable more grounded in reality. Rampaging prehistoric monsters are replaced by unfaithful women and gangsters. But, much like Beasts, Mud is at heart the story of mighty forces encroaching on children's innocence. 

The film centers on Ellis (Tye Sheridan) and Neckbone (Jacob Lofland), buddies who spend their days aimlessly cruising the river until they discover a boat lodged in a tree. They soon encounter Mud (Matthew McConaughey), a disheveled fugitive hiding out on an isolated island, waiting for his love to join him so they can flee. Drawn to his charisma, Ellis plays Pip to Mud's Magwitch, delivering food and supplies in hopes of proving that true love conquers all. Meanwhile, vigilantes and crooked cops home in on the island. 

It's a remarkably simple setup, but anyone who has seen Nichols' brilliant Take Shelter knows nothing is ever black and white with his films. What seems like a cut-and-dry tale of a mythical bum is instead a rich story of adolescent confusion. Each choice the boys make to help Mud reunite with Juniper (Reese Witherspoon) comes steeped in consequence, whether it's the guilt that comes with stealing or the secrecy that isolates them from friends and family. Add to that the divorce of Ellis' parents and Neckbone's feelings of abandonment, and the emotional heft is staggering.

It's also a lot for young actors to handle, but Sheridan and Lofland shoulder it beautifully, matching the experienced ensemble step by step. McConaughey meshes Mud's conflicted morals and his mysticism. He's at once larger than life and completely rudderless, depending on the boys' moods during each meeting. 

Central to the entire narrative, though, is the river. As in The Adventures of Huckleberry Finn—another tale of a child and fugitive—it functions almost as a character, rising and falling with the narrative, hiding secrets in its murky depths and moving everything forward with its current. Mud is far from perfect, but it's almost impossible not to get swept away by it.

Critic's Grade: B

SEE IT: Mud is rated PG-13. It opens Friday at Clackamas, Fox Tower.