A close-up of a man wearing glasses and a cap, looking into the distance with a serious expression.

Cantankerous, charismatic and passionately committed, John Lipscomb reflects on his 25 years patrolling the Hudson River, traveling more than 80,000 miles by wooden boat.

Movie poster for 'The Keeper' featuring a man with a dog on a dock, a boat, an island, and a city skyline during sunset with dramatic clouds.

Like many rivers around the world – the Hudson, America's First River and the Birthplace of the American Environmental Movement – boomed as a growing human population used it for transportation, sustenance and, for many years, a dumping ground.

The river paid a price for all this use and abuse, struggling against its share of contamination. For the past nearly three decades the river's poet laureate and literal "eyes on the river," Captain John, has been at the forefront of each of those fights, taking on industrial and human pollution, suffering the losses and celebrating victories.

While he has had successes on the Hudson, committing a life to protecting a river is a never-ending fight. Today, John Lipscomb is one of more than 300 “Keepers” around the globe, looking out for their respective rivers.

Produced by Carolyn Marks Blackwood and Jon Bowermaster.

Directed by Jon Bowermaster.