In rural New Zealand, child services worker Paula and police officer Andy bring 13-year-old Ricky, a Maori orphan, in a police car to Bella's farm. Bella is so happy to meet her new foster son. Paula explains, as the audience sees brief flashbacks, all the trouble Ricky has gotten into and advises Bella that Ricky will be a challenge. Bella is not bothered and she calls herself his aunt. Ricky is reluctant and even returns to the police car. But Bella has given Ricky a nice room with books, since he likes to read. Ricky is also quite familiar with movies and music and seems to like the Internet.Hec, who is 65 years old and looks like Sean Connery, returns from hunting with dog Zag, carrying a large pig. He is not as pleased as wife Bella about the new addition to the family, but "Uncle", as Ricky will call him, grudgingly accepts his situation.After he is supposed to be in bed, Ricky takes a flashlight and wanders off. It appears he has traveled a long way, but Bella finds him sleeping a mere 200 yards from home. Breakfast is ready.Ricky wonders what to do, so he is given chores. Bella teaches him about customs she follows and talks about what she believes will happen when she dies.Hec takes Ricky hunting but, while he seemed to enjoy creating poetry about disgusting and morbid topics, Ricky is squeamish when an animal is actually killed.Ricky celebrates a birthday, which he has never done. There is a cake, and he gets his own dog who he names Tupac, after the rapper.One day Ricky goes off by himself only to return and see Hec crying.After a service at the church, Ricky and Hec are back home. Child Services has sent a notice that Ricky's situation will be evaluated. Heck says they expect a woman, and Ricky wonders why they can't just find another one. Hec says it doesn't work that way, and he says it was Bella, not him, who wanted a child.Feeling rejected, Ricky writes a suicide note, sets a barn on fire, and runs away with Tupac. He is determined to live on his own in the bush rather than go back to "juvie". However, Hec finds him while hunting with Zag. Ricky had indicated he wanted to live in the bush and Hec has already said Ricky wouldn't make it. In fact, Ricky can't live without toilet paper. But when Hec falls and hurts his leg, they will have to cope without modern conveniences for a while. Also, Ricky is shocked to learn Hec doesn't know how to read.Paula and Andy visit the farm and find the note and the barn burned, but Paula is not convinced Ricky is dead, and she believes a grieving Hec might have done something desperate. She is determined to find the boy, and a search begins.Ricky helps Hec but isn't very good at hunting. However, Hec has eel to eat.Once Hec is able to walk using a makeshift crutch, he and Ricky start walking. Hec isn't interested in returning to the farm because that was Bella's and he wasn't good at farming. He also reveals he too spent time in prison for a mistake when he was a lot younger.Soon, Hec and Ricky find a shelter and they go inside to see what food and supplies they can find. On the wall is a newspaper article with their pictures and ages. They are celebrities because their story has become big news. Three hunters return and they recognize Hec and Ricky. However, it is believed Hec may have kidnapped Ricky and may be dangerous. Ricky doesn't help matters when he describes their relationship in a way that makes Hec sound like a pedophile. Hec gets in a fight with the hunters. Ricky fires his gun, and the hunters give up their weapons and let Hec and Ricky go. Hec is moving a lot faster now.While they are in the wilderness, Hec and Ricky see a bird that was believed extinct. If they can provide proof they will be famous, but they don't have a camera. Also, because Ricky has compared their trek to that of the African wildebeest, Ricky decides he and Hec are Wilderpeople.Numerous people in uniform have joined the search for Hec and Ricky. They question the hunters.Hec and Ricky find another shelter, and a man who appears to be dead. He is not, however, so Hec agrees to stay with the man, a ranger who is diabetic, until help arrives. Ricky goes for help.Ricky sees Kahu, a beautiful girl, on a horse. She recognizes him and takes him back to her house. At first she claims her parents are deceased but then admits she was kidding. Her mother works for a resort, and her father comes back soon. Ricky tells his story. His mother abandoned him and he doesn't know anything about his father. Where he lived, there was a girl Amber who died after being placed with a family. Ricky doesn't want to end up back in "juvie". After Kahu performs a song she wrote, Ricky falls asleep and is worried when he wakes up because he wasn't supposed to be gone that long. Kahu takes him back to where the man was found. The people searching for him are there, and Hec is gone, so Ricky takes off.Paula and Andy find Ricky but can't capture him because of a large ditch between them. Paula wants Ricky to admit Hec mistreated him but he won't.Hec and Ricky reunite and are on the run again. During their time in the bush, they encounter a pig who the dogs try to attack. Tupac survives but Zag does not. Hec and Ricky make a pile of rocks with the word "Zag".Also, they have been gone for so long that it is now winter, and it snows.At a lake, Ricky dumps Bella's ashes, which Hec didn't realize he brought. Bella had indicated she would go to a lake in the sky, and Ricky believes this was the place she would want to be.Hec and Ricky are reunited with the hunters, but they aren't any nicer, so Hec and Ricky just steal from them.One day Hec and Ricky see a moving bush. It turns out to be a crazy man named Sam who has lived in a trailer for 15 years and believes in wild conspiracy theories. He puts metal hats on Hec and Ricky so the government can't read their minds. Hec and Ricky stay the night but need a way to leave. Sam has a pickup truck and Ricky figures out how to start it. The uniformed men are close, so Ricky starts driving fast and recklessly. The chase includes the army after they arrive in a desert which is used for training.Eventually, Ricky crashes the truck through a fence and wrecks in a junkyard. There is no way to get away, so Hec wants to give up. Ricky continues to resist, accidentally shooting Hec, but both are eventually taken away.In a courtroom, a decision is made about what will happen to Ricky.Hec is later shown in what looks like a large European stone fortress, and then in a halfway house after he did his time. He is learning to read. Ricky comes to visit, and Kahu and her father are nearby. Ricky and Hec have a nice conversation. Hec agrees to come live with Kahu's family and they eventually go off to search the bush for that bird.