The film begins in the depths of the schooner La Amistad, a slave-ship carrying captured West Africans into slavery. The film's protagonist, Sengbe Pieh, most known by his Spanish name, "Cinqué," painstakingly picks a nail out of the ship's structure and uses it to pick the lock on his shackles. Freeing a number of his companions, Cinqué initiates a rebellion on board the storm-tossed vessel. In the ensuing fighting, several Africans and most of the ship's Spanish crew are killed, but Cinqué saves two of the ship's officers, Ruiz and Montez, whom he believes can sail them back to Africa.
After six weeks have passed, the ship is running out of food and fresh water, and Cinqué is growing angry with Yamba who believes keeping the Spaniards alive is the only way to get back to Africa. During the night, they pass another vessel, carrying a group of wealthy English-speaking passengers having a dinner party on deck. The next day, they sight land. Unsure of their location, a group of African men takes one of the ship's boats to shore to fetch fresh water. While there, La Amistad is found by a military vessel bearing an American flag - the Spaniards have tricked the Africans by sailing directly for the United States.
Captured by the American Navy, the Amistad Africans are taken to a municipal jail in New Haven, Connecticut, where the ship's occupants, and a tearful Cinqué, are thrown into a grim dungeon, awaiting trial.
The film's focus now shifts to Washington, D.C., where a session in the House of Representatives introduces John Quincy Adams (Anthony Hopkins), the elderly former President and politician. While strolling in the gardens, Adams is introduced to two of the country's leading abolitionists; the elderly freed slave Theodore Joadson (Morgan Freeman) and Christian activist Mr. Tappan (Stellan Skarsgård), both of whom are leading shipping magnates in New England and co-proprietors of the pro-abolitionist newssheet "The Emancipator". The