One of the largest forests on the planet is under threat! Composed of aquatic trees reaching 70 meters high, this plant world is one of the richest ecosystems in existence…facing an invisible threat.

As the true source of life and biodiversity, this ecosystem is of crucial importance for the balance of the environment and the species of animals that live there. But for the last few decades, these Kelp Forests have been dangerously decreasing. This documentary takes the viewer on a journey of kelp forests, from Australia to California through Brittany. It explores the consequences, causes and threats that face these magical ecosystems.