Ten years have passed since high school for three friends, [Jerry](more/actor/matthew-lillard), [Dan](more/actor/seth-green), and [Tom](more/actor/dax-shepard), when they learn of the tragic death of their childhood companion, Billy, in a parasailing accident in Costa Rica. After attending his funeral, they take a nostalgic trip to their old treehouse where they spent countless hours as kids. To their surprise, they discover a treasure map related to D.B. Cooper, which Billy had been pursuing throughout his life.
Eager for adventure, Dan decides to take a leave of absence from his medical career to join Jerry and Tom on a camping expedition in search of this legendary treasure. They navigate down the river, eventually reaching a rock formation known as Grandpa's Nose, where they pitch camp for the night. Around the campfire, they realize they've forgotten to pack food. In an attempt to alleviate their hunger, Tom sets out fishing, but his misadventures lead to an unexpected encounter with a grizzly bear.
> "Bear! Run!"
The bear gives chase, and in a twist of fate, Dan falls behind only to be mistaken for the bear's cub and whisked away to the bear's den, where he is coerced into consuming a mangled squirrel. After a daring escape, the trio finds shelter for the night in a tree, only to wake up the next morning to find their supplies—and Dan's cellphone—ruined by the bear, which has also damaged their treasure map.
As they float down the river, misreading the map leads them into treacherous rapids and ultimately over a waterfall. Miraculously, they survive the plunge but are left with a wrecked canoe. They venture into the woods, relying on a compass to guide them, only to stumble upon a pot farm run by the aggressive duo of Dennis and Elwood, who mistakenly believe the friends are intruders and open fire.
In a desperate bid to escape, the boys find themselves in a surreal situation when their troubles worsen as they become stoned from the smoke released during the scuffle. They make a narrow escape into a pond, evading the farmers. At dawn, the farmers, furious over their destroyed crop, set out to find and eliminate them.
The friends later encounter two hippie girls who offer camaraderie and nourishment as they stay in their lofty tree. However, the farmers track them down using the radio, leading to a chaotic situation where the girls retaliate with bags of feces to distract the men and aid the guys' escape. Now half-naked and rain-soaked, the three friends must cling to one another for warmth and survival.
Just when things seem bleak, they are rescued by a reclusive man named [Del Knox](more/actor/burt-reynolds), a former partner of D.B. Cooper. He provides them with clothes and safety in his mountain hut. However, their refuge is short-lived as the farmers launch an assault. Del retaliates with his gun, giving the boys a chance to flee.
Eventually, they discover the tragic site of D.B. Cooper's crash and uncover his remains along with the fateful suitcase holding his share of the money—which, heartbreakingly, he had set ablaze for a fleeting moment of life. They pay their respects by leaving tokens from their lives, including memorabilia from their childhood.
The confrontation reaches a climax when the farmers corner Jerry and Tom. In a flurry of chaos, Jerry accidentally drops a grenade he snatched from one of the farmers. With moments to act, he hurls it at the assailants. The ensuing explosion causes a tree to crash down on them, resulting in their capture.
In the aftermath, Jerry, Dan, and Tom reap the rewards of their harrowing adventure by receiving a portion of the remaining treasure from D.B. Cooper's partner. Jerry proposes to his girlfriend, Dan embarks on a romantic relationship with one of the hippie girls, marking a personal milestone, while Tom becomes a camp counselor who excitedly recounts his outrageous camping expedition to his group of eager kids.
