Righteous, captivating and entirely successful as single-issue-focused documentaries go, Gabriela Cowperthwaite’s film draws on startling video footage and testimonies from former orca trainers, building an authoritative argument on behalf of this majestic species.

The movie makes a strong case against the captivity of killer whales under sub-circus conditions, but the stance is made even more horrifying because so little has changed in the history of the organization. Blackfish is less balanced investigation than full-on takedown of a broken system.

Focusing on the notoriously aggressive orca Tilikum, this gripping film presents a persuasive case against keeping the species – and by extension any wild animal – in captivity for the purposes of human entertainment.

The movie is revealing, wrenching, and important, a reminder that what feels wrong in our gut—the effort to turn free-roaming and unknowable beasts into caged vaudevillians—is always worth investigating.

This is as thorough a take-down of a business and its practices as you’re likely to ever see.