Zak runs away from his care home to make his dream of becoming a wrestler come true.
Zak is a 22-year-old man with Down syndrome that lives in a nursing home. He dreams of being a wrestler and to be taught by his idol, the Salt Water Redneck. With help from his roommate Carl, Zak breaks out of the nursing home and runs away. A nurse named Eleanor is tasked with bringing Zak back.
Zak meets Tyler, a loner who goes on the run after he angers local thugs Duncan and Ratboy after stealing their crab pods and then burning their gear. Although Zak annoys Tyler, he takes Zak along with him when he meets Eleanor and sees that she is looking for him. Tyler also feels guilty over an incident from years earlier where he fell asleep at the wheel and got into an accident that killed his brother Mark. He and Zak form a bond along the way, and Tyler agrees to take Zak to Ayden, NC to find Salt Water Redneck.
Eleanor finds the two and begrudgingly joins them on their trip. She is told by her boss that he wants to have Zak committed to an institution meant for people with serious problems. She is given the address to Salt Water Redneck’s home, only for the three to find that he closed his wrestling school that Zak wanted to go to a long time ago. However, after learning that Zak is a huge fan, he agrees to show him some wrestling moves. He even puts Zak in a tournament for fun, only for his opponent to go rough on him and call him rude names. Zak then surprises everybody by performing a move where he throws the opponent out of the ring, just as Duncan shows up to beat Tyler.
In the end, Tyler survives but with some injuries, and he, Zak, and Eleanor retreat to Florida as a family.
The film opens in a nursing home. Zak (Zack Gottsagen) is a 22-year-old patient with Down syndrome. He asks for a pudding cup during mealtime and gives it to an elderly patient, plus a drawing that Zak made that appears to be a plan. The old lady gives him a thumbs up and goes along with it. After eating the pudding, she pretends to be falling ill, which gives Zak a chance to make his move and run away. Unfortunately, just as he makes it outside, he is tackled by orderlies.
Zak is a huge fan of the wrestler known as the Salt Water Redneck (Thomas Haden Church), and it is his dream to become a pro wrestler. He watches an ad for Salt Water Redneck’s wrestling school in Ayden, NC. Zak’s main nurse, Eleanor (Dakota Johnson), comes in to tell him that his privileges have been revoked since this is his second attempt at an escape, and Eleanor has had to label him a flight risk.
A loner named Tyler (Shia LaBeouf) is dismissed at his job because his boss knows that Tyler has been stealing crab pods from local thugs Duncan (John Hawkes) and Ratboy (Yelawolf), and they are coming to retaliate. Tyler sits outside, and the boss comes to talk to him sincerely, saying that Tyler’s brother Mark (Jon Bernthal) would not be wanting him to steal from others. Tyler has flashbacks about his time with Mark.
That night, Zak is helped by his roommate Carl (Bruce Dern) to escape by pulling the bars on his window. Zak rubs soap on his body to help him squeeze out. He runs until he hides in a boat. The following morning, he witnesses Duncan and Ratboy, plus a third goon, confronting Tyler about the stolen crab pods, and they start to beat Tyler before Duncan threatens to kill him if he messes with them again. Tyler ends up burning a bunch of valuable gear that belongs to Duncan and Ratboy. Just as they notice, Tyler hops on the boat where Zak is, and the two thugs chase after him. Tyler rides the boat until he finds a spot to hide. Zak almost blows their cover because he throws up, but Tyler manages to keep them hidden until Duncan and Ratboy get lost.
Back at the nursing home, Eleanor’s boss Glen orders her to bring Zak back since he knows that Zak is particularly fond of her.
Tyler plans to head off on his own, but Zak follows him. He begins to annoy Tyler by calling his name out repeatedly and asking him a bunch of questions, while also continuously mentioning his love for wrestling. Tyler leaves Zak by a lake to ride with someone else, only to later find him being harassed by a kid who is trying to make Zak jump off the high dive, even though he cannot swim. Tyler orders the boy to stop, but he pushes Zak off. Tyler punches the boy in the face and then jumps in to pull Zak out of the water. Zak continues to follow Tyler and annoy him more.
Tyler stops in a shop for supplies, though he frightens the shop owner since he is carrying guns. Tyler drops them and shares a drink with the man. Eleanor then walks into the shop to ask about Zak, as she has been doing with everyone in town. Tyler is dodgy about having seen Zak, but he ultimately doesn’t tell Eleanor that he is with him. Tyler decides to let Zak continue joining him without any fuss, and Tyler agrees to help Zak get to Ayden to meet Salt Water Redneck.
On their journey, Zak and Tyler must cross the river, but since Zak can’t swim, Tyler makes him floaties to get across the water. A shrimp boat starts sailing in their direction, so Tyler swims as fast as he can and manages to pull Zak forward before he gets struck by the boat. Tyler then starts to teach Zak how to swim. They later set up camp for the night. Zak tells Tyler about his desire to become a wrestler, and how he wants to be a bad guy character in wrestling. Tyler asks why, and Zak mentions how people like his coach would call him a “retard” and make him feel like a bad guy. Tyler assures Zak that those people are just assholes and that he has the heart of a good guy. When Zak asks Tyler is he is a good or bad guy, Tyler isn’t sure how to answer. He has another flashback to him and Mark, in which Tyler was driving them together but fell asleep at the wheel, and it is implied that this is how Mark died, and Tyler has been carrying the guilt ever since.
In the morning, the two continue walking. Tyler shows Zak how to fire a rifle. They find a boat and try to take it for themselves, but they are stopped by a blind man with a gun named Jasper. After they prove they are harmless, Jasper invites the two to join him for a sermon he performs with others in the area, and he baptizes them before helping them make a raft with logs to help them continue on their way. On the water, Zak assures Tyler he is a good guy, and it moves Tyler to tears. The two then rest again for the night, where Zak comes up with his own costume and wrestling name, “The Falcon.” He then takes some peanut butter that Tyler bought from the shop and smears it on himself, re-dubbing himself, “The Peanut Butter Falcon”.
The next day, the two are found by Eleanor. She gets ready to bring Zak back, but he takes her car keys and tosses them into the ocean. This leaves her no choice but to join Tyler and Zak on their trip to Ayden. Tyler and Eleanor argue about Zak being brought back to the nursing home, since they both know that he doesn’t belong there, but his own family abandoned him, so he has nobody else to look after him. They eventually stop on another island to rest again, and Eleanor begins to warm up to Tyler after seeing how Zak has taken to him. Later that night, they are found by Duncan and Ratboy, who have been tracking Tyler all along. They burn down their raft, but before they go after Tyler, Zak steps in to protect them with his rifle. Duncan and Ratboy leave but promise that this isn’t over.
The three are forced to keep walking until they reach a diner to get food. Eleanor talks to Glen about having found Zak, but Glen wants to have Zak sent to an institution, Cherry Hill, where, as Eleanor notes, is usually designated for junkies and prostitutes. Eleanor then talks to a waitress, who knows who the Salt Water Redneck is after his name is mentioned. Eleanor asks her if she knows where he lives.
The trio is directed to the home of Salt Water Redneck, who is now retired and just goes by Clint. Tyler approaches his front door to ask him about his wrestling school, but Clint says it’s been closed for ten years, meaning the ad that Zak saw was just an old tape. Tyler understands but lets Clint know just how big of a fan of his Zak is. After waving to Zak, the trio start to walk away again, but Clint drives up in his Salt Water Redneck appearance and agrees to teach Zak some wrestling moves for fun. Zak is over the moon.
Clint then brings the trio to a wrestling show that he holds in the neighborhood. Zak is set to go up against a big man named Sam (Jake Roberts). Tyler locks Eleanor in Clint’s truck to keep her from stopping Zak from following his dream. While she tries to get herself out, she sees Duncan and Ratboy arriving. Tyler goes to see Zak in the ring, but he gets ruthlessly tossed around by Sam, who was told to go easy on Zak but refused to listen. Eleanor breaks herself free as she goes to warn Tyler. Zak then musters up his strength and performs a Salt Water Redneck move that he wasn’t taught, in which he lifts Sam over his shoulders and tosses him out of the ring, to the amazement of everyone watching. Eleanor runs in too late, as Duncan runs up to Tyler and hits him over the head with a tire iron.
Zak and Eleanor are in the hospital, waiting to hear about Tyler. Eleanor talks to the doctor, and she starts crying. Zak holds a cupcake (it’s his birthday) and he makes a wish before blowing out the candles.
Sometime later, Eleanor is driving Zak somewhere. They end up in Florida, where Tyler had wanted to go with the two of them. Zak then turns around to wake Tyler up, as he is still alive, though still recovering from his injuries. Zak smiles as they enter their new home.