Tilikum is a six-ton orca captured off Iceland as a calf and shipped through a succession of marine parks before ending up at SeaWorld Orlando, where he has killed three people, including veteran trainer Dawn Brancheau in 2010. Director Gabriela Cowperthwaite builds the film around interviews with former SeaWorld trainers, who describe being told the whale nicks and scars on other orcas' skin were just "rough play," and marine biologists who lay out what orca brains and social bonds look like in the wild versus a concrete tank. Archival footage of Tilikum's capture, home video from inside SeaWorld's shows, and courtroom and news material about the Brancheau death anchor the case. Former trainers describe being fed misinformation about orca lifespans and behavior, and the film traces how a captive-bred population with disrupted family structures produces animals that never show comparable aggression toward humans in the ocean. SeaWorld declined to be interviewed on camera. The film became a flashpoint in the debate over marine mammal captivity and was followed by real changes to SeaWorld's breeding and show programs.