Mustangs and Rengades follows filmmaker James Anaquad Kleinert as he documents his relationship with a band of wild horses living freely in Disappointment Valley, Colorado. Led by the iconic stallion Traveler, the herd faces brutal government helicopter roundups that separate them and push them to the brink of extinction. James investigates the Bureau of Land Management's (BLM) role in these roundups and uncovers the influence of extractive industries like oil, gas, and mining on public lands. Labeled a potential eco-terrorist and under government surveillance, James partners with a FOIA attorney to challenge the surveillance. He relocates to Norway due to fear and stress, where his work finds greater receptiveness. Returning to the US, he takes his case against the BLM to federal court and wins, setting precedent for public records and legal proceedings. Despite challenges, James continues to shed light on the plight of wild horses, public lands, and corporate-government collusion in the American West.