Cannes moored up on the Mississippi on Saturday with "Mud", a Huckleberry Finn-like tale about two boys, a fugitive, and the search for true love that wrapped up the race for the Palme d'Or.
Set in a richly-evoked American south of makeshift houseboats, untamed nature and hardscrabble lives, the coming-of-age story by US director Jeff Nichols is one of 22 films vying for the Riviera festival's top award Sunday.
It tells of two teenaged boys, 14-year-old Ellis and Neckbone played by real-life southerners Tye Sheridan and Jacob Lofland, who stumble across a man hiding out on an island in the middle of the river, going by the name of Mud.
Shaggy-haired, dirty, but ultimately unthreatening, the character played by Matthew McConaughey has set up camp in a boat marooned in a treetop by a flood, and which they had hoped to claim as their own.
Hard-up for supplies, Mud strikes a deal with the kids: bring him food to survive in hiding and when he moves on, the boat -- and his pistol -- will be theirs.
Soon enough his story comes out: hopelessly in love with his childhood sweetheart, he shot dead one of her lovers after he savagely beat her, and now has both police and bounty hunters on his tracks.
Moved by the story -- all the more since he is in the throes of first love and his parents' marriage is on the rocks -- Ellis sets his heart on reuniting Mud and his beloved Juniper, played by southern belle Reese Witherspoon.
But the victim's thuggish relatives and their gang of hired guns have the pair in their sights as well.
The 33-year-old Nichols said he wanted with his third feature film to tell a universal story about unrequited love.
"It was really about this boy desperately searching for a version of love that works -- and the adults around him are just really bad examples," the film-maker said.
But it was also a chance for the director, born and raised in Arkansas, which is bordered by the mighty Mississippi, to conjure a riverside way of life in danger of dying out in an increasingly conformist America.
"I wanted to capture a snapshot of a place that might not be there forever," he told reporters before the film's red-carpet premiere. "There's no greater river in the world in terms of the stories that have been birthed from it."
"I like big, sweeping movies and I like applying that idea to these places that I come from," he said.
The director joked that he "stole" ruthlessly from Mark Twain's "Huckleberry Finn", whose boy heroes Huck and Tom Sawyer meet the slave character Jim on an island in the Mississippi.
"Mark Twain really was able to encapsulate what it was like to be a child growing up on the Mississippi river," added Nichols, who has been haunted by the books since childhood and made them required reading for his young stars.
"Yeah, me and Tye got to read Huck Finn on the set," Lofland confirmed. "And we found a lot of stuff that happened to wander onto the script -- we did question Jeff on that one!"
Nichols' lead actors in the film all hail from the American south, the two youngsters bringing some locally-honed skills to the shoot.
"It was remarkable finding these boys that could ride dirt bikes, run boats," he said. "I'd say say, 'Hey, jump down that hole and I'll throw snakes on you,' and they'd say 'All Right!"
McConaughey too relished a chance to plunge himself back into the rivers and creeks of his youth, as well as into the spirit of first love.
"Puppy love, there's nothing reasonable about it, thank God," he said. "My character is a dreamer. If he ever got pragmatic or reasonable he would come back down to earth and die of heartache."