Amidst fireflies and mangroves, the musician Papámarimba narrates the legend of El Libertario. A story about a ghost ship, a slave rebellion and the eternal struggle for freedom. But his son Canchimalo no longer believes in these stories. He thinks they are just superstitions, keeping his people in backwardness. A challenge that will bring him face to face with the spirits of his ancestors.

As the tide rises and falls, María de los esteros spends her life in the mangroves, groping in the mud, looking for shells, digging up memories. She is joined in the task by her memories and the singing of her deceased friends who are still digging up shells.