Like a crime-fighting superhero of the high seas, Sea Shepherd founder Paul Watson has spent his life sailing the globe to keep our oceans and their inhabitants safe.

A daring ship’s captain with no fear of danger, Watson and his crews have confronted illegal whaling vessels from Europe to the Southern Ocean, seal hunters in Canada, and shark finners in Central America. Impervious to threats, with more than one nation issuing warrants for his arrest, Watson continues to intervene on behalf of his “clients”: the ocean creatures endangered by overfishing and illegal activities on the high seas.

As a teenager in the 1960s, Watson left an abusive home and shipped out as a deck hand on a merchant vessel. Upon his return he helped found Greenpeace, putting himself in harm’s way to protect marine mammals. But in 1977, when his bold interventions got him kicked off of Greenpeace’s board of directors, he launched Sea Shepherd with a ragtag crew and a single ship. Four decades later, the direct-action group has chapters around the world and an international fleet of 13 ships, the world’s largest private navy.

Blending revealing contemporary interviews with Watson, archival clips of Sea Shepherd’s dramatic encounters, and spectacular underwater nature footage, award-winning documentarian Lesley Chilcott (An Inconvenient Truth, Waiting for “Superman”) paints a fascinating portrait of a man willing to put his own life and liberty at risk in a relentless quest to protect the oceans and the marine life within.