The narrative opens by detailing the majestic construction and luxurious appointments of the steamship Titan, an engineering marvel deemed completely unsinkable due to its watertight compartments and steel hull. Because of this absolute perceived safety, the operating company cuts corners on lifeboats and establishes a disastrous navigation rule to maintain full speed through fog and storms to break Atlantic crossing records.
Amidst two thousand passengers, a disgraced former naval officer named John Rowland works as a common sailor on board, tormented by his past rejection and a lingering obsession with a former love, Myra Selfridge, who is also a passenger. Rowland holds a bleak, atheistic worldview centered on an immutable law of cause and effect, contrasting sharply with the conventional religious beliefs of the passengers around him.
On a bitterly cold night in the North Atlantic, while steaming at full speed through thick fog, the Titan collides with a deep-laden sailing ship, cutting it in two. The officer on watch suppresses reporting the disaster to protect the company, but Rowland, who witnessed the horrific event from the crow's-nest, refuses a bribe and vows to expose the reckless homicide.
To discredit his testimony and induce hallucinations, the captain has Rowland secretly drugged with a preparation of Indian hemp. During a subsequent watch while under the influence, Rowland experiences bizarre, apocalyptic visions of his past and the universe while a sleepwalking child wanders onto the bridge and seeks refuge with him.
Moments later, the Titan plunges at full speed into a massive iceberg. The impact shears off the starboard bilge, crushing the ship against the ice and sending heavy engines and boilers crashing through the bulkheads, which kills the engineering staff and shatters the vessel before it slips beneath the sea.
In the aftermath, Rowland finds himself stranded on the iceberg along with Myra's young daughter, whom he rescued. He is forced to fight and kill a polar bear with a pocket knife to ensure their survival before they are finally rescued by a passing bark and taken to Norway.
The final section moves to the insurance offices in London, where an investigation unfolds regarding the disaster and the concealed collision with the sailing ship. Through Rowland's testimony and the complex maneuvers of underwriters, the truth is exposed, leading to the financial ruin of the steamship company's stakeholders, while Rowland is ultimately reunited with Myra and her family.
