In the early 1800s, Owen Chase (Chris Hemsworth) is offered a spot as First Mate on the New England whaling ship Essex. The problem is, he was promised a position as Captain on the voyage, but George Pollard (Benjamin Walker), the less-experienced son of a wealthy sailing family, has been given that post instead. Chase almost turns it down, but when he gets a promise in writing that he won't be overlooked next time, he agrees to sign on.
Under Pollard's inexperienced direction, the sailors endure hardship and although they harpoon and kill one whale for its oil, they don't want to go back home until they've found more. They sail south where they hear there have been whale sightings. As they're about to harpoon more whales, the vessel is attacked by a whale of mammoth size and will. The real-life maritime disaster went on to inspire Herman Melville's classic novel, Moby-Dick.