Grizzly Man

Herzog used sequences extracted from more than 100 hours of video footage shot by Treadwell during the last five years of his life. He also conducted and filmed interviews with Treadwell's family and friends, as well as bear and nature experts. Park rangers and bear experts commented on statements and actions by Treadwell, such as his repeated claims that he was defending the bears from poachers. A bear researcher clarifies that the incidence of poaching on Kodiak Island was low, but Sven Haakanson, the director of the Alutiiq Museum, notes that Treadwell's actions may have put the bears at risk by habituating them to human contact. Treadwell also claimed that he had "gained the trust" of certain bears, allowing him to approach and pet them. A local pilot speculates that the bears were so confused by Treadwell's direct, casual contact that they were not sure how to react to him.
In 2003, Treadwell was camping in Katmai National Park with his girlfriend, Amie Huguenard. Treadwell usually left the park at the end of summer but that year stayed into early October. This put him and Huguenard at greater risk, as bears are aggressive during this period and search for food to store up calories for hibernation during the winter. Herzog speculates that staying later in the season ultimately resulted in the couple's being attacked and killed.
Willy Fulton was the pilot who discovered the few remains of the couple and reported them to the National Park Service. He notes that he saw a lone man's arm with a wristwatch, and could not keep the image out of his mind. After an investigation, the coroner and park police gave the wristwatch to Jewel Palovak, an ex-girlfriend of Treadwell's. He had bequeathed her his belongings. These included his video camera, which captured an audio recording of the attack.
In addition to presenting views from friends and professionals, Herzog narrates and offers his own interpretation of events. Treadwell seems to have been fond of animals since childhood. It is suggested that his unsuccessful career as an actor, including allegedly losing a role to Woody Harrelson in Cheers, led him to make a name for himself in the wild. Herzog concludes that Treadwell had a sentimental view of nature, thinking he could tame the wild bears. Herzog notes that nature is cold and harsh; Treadwell's view clouded his thinking and led him to underestimate danger, resulting in his and Huguenard's deaths.
Palovak gave Herzog permission to listen to the audio recording of the attack. He refrained from making this a part of the film, but was filmed listening to it and reacting with distress. Herzog initially advised Palovak to destroy the audio recording rather than listen to it or keep it.
In a later interview, he repudiated his own advice, saying it was:

Stupid... silly advice born out of the immediate shock of hearing—I mean, it's the most terrifying thing I've ever heard in my life. Being shocked like that, I told her, "You should never listen to it, and you should rather destroy it. It should not be sitting on your shelf in your living room all the time." [But] she slept over it and decided to do something much wiser. She did not destroy it but separated herself from the tape, and she put it in a bank vault.
Around 2023, Palovak destroyed the tape.