In the heart of the Atlantic Ocean, a mysterious and vital ecosystem thrives, largely unseen by human eyes—the Sargassum seaweed. Sargassum is a visually captivating 90 min documentary that uncovers the seaweed's ecological significance and the intricate relationships it holds with marine life and humanity. Experts shed light on the critical role Sargassum plays in marine biodiversity, acting as a nursery and a sanctuary in the open ocean. However, the documentary takes a poignant turn as it investigates the alarming proliferation of Sargassum, particularly in the Caribbean and southern US. Once a symbol of ecological balance, Sargassum has now become an environmental menace, overwhelming coastlines and disrupting local economies.