When a couple of 14-year-old Arkansas boys find a cabin cruiser fifteen feet up in a tree on an island in the Mississippi River, you can tell we’ve entered Huckleberry Finn territory, where freedom and truth are on the river, while violence and betrayal are on the land.  Just to make it clear, the title character – “Mud,” played by Matthew McConaughey —  is a superstitious man with a cross pattern in a boot heel – just like Huck Finn’s father.

Matthew McConaughey with young helpers

McConaughey is on the run after having gunned down the man who beat up his sometime girlfriend, Juniper,  played by Reese Witherspoon, who is much better as a tramp than she is in her usual ingénue roles.  The police are looking for Mud, but he has little to fear from them.  His problem is with his victim’s father and brother and hirelings, who are out to kill him.

The boys who encounter him on the island are played quite brilliantly by Tye Sheridan as Ellis and Jacob Lofland as Neckbone, or Nick.  Tye is the more romantic and Nick the more level-headed, and both are utterly believable as boys who have already seen too much of life and are struggling to make sense of it.

They do their best to help Mud escape the island and reconcile with Juniper, but reality intrudes and their lives are in jeopardy until a mysterious neighbor sets things right with a sniper rifle.  There is no Southern Gothic without sudden and explosive violence.

The cast is wonderful, with Joe Don Baker as the revenge-seeking patriarch and Sam Shepard as the neighborhood sharpshooter. The film belongs to McConaughey, who demonstrates that he can thoroughly inhabit a character.  But it wouldn’t be a coming-of-age film without Sheridan and Lofland, who see more of life in a few weeks than most people see in their whole lives.

The film would have benefited from some editing – Ellis’s infatuation with older girl takes up too much time – and the ending is pat, but the story is well-told and the acting is well worth watching. McConaughey has been on a tear lately to prove that he is more than a hunk and an action hero, and “Mud” serves that purpose admirably.