Spots 
Mark Strong tolerates the strange behavior of Martin Hall while traveling across France toward Paris. Hall drops his foolish facade on the train, revealing immense inner gravity and urgent foreboding. He entrusts Mark with a sealed packet of papers, begging him to open it only if death strikes within three days. This sudden bequest shifts a casual acquaintance into a dangerous mission.
Part 1
Martin Hall leaves Paris abruptly for Dieppe to embark on a perilous voyage. Soon after, a sinister Irish seaman delivers an invitation from Captain Black, offering Mark entry aboard his mysterious vessel. Recognizing the hidden danger facing Hall, Mark refuses the invitation and prepares to head for Plymouth. Accompanied by Roderick and Mary, he hastens back to sea to protect his companion.
Part 2
Martin Hall's posthumous papers reveal Captain Black's possession of treasures from missing ocean liners, proving a secret commerce in oceanic plunder. Armed with this confession, Mark seeks help from Admiralty officials in London, only to be dismissed by bureaucratic indifference. He then turns to the Black Anchor Steamship Company, offering to track down Black and the mysterious warship. Driven by Hall's legacy, Mark prepares to cross the Atlantic to investigate further.
Part 3
A shimmering golden warship moves across the Atlantic at impossible speed without emitting steam or smoke. Aboard the Celsis, Mark and his crew watch in horror as the vessel shell-fires the liner Ocean King, signaling her to halt. Mark recognizes Captain Black on the bridge, confirming Hall's terrifying story of an unstoppable sea raider. The sudden arrival of American naval warships forces the golden phantom to break off its attack and vanish.
Part 4
Arriving in New York City, Mark tracks the suspicious Italian crewman Paolo ashore into the squalid taverns of the Bowery. Disguised in sailor attire, Mark enters a filthy saloon frequented by thieves, sailors, and cutthroats. He observes Paolo meeting with Captain Black's ruthless lieutenants, including Roaring John and Four-Eyes. Maintaining his disguise under the gaze of hostile onlookers allows Mark to remain undetected while gathering intelligence.
Part 5
Taken captive aboard the nameless vessel, Mark finds himself treated with unexpected luxury while being transported deep into Arctic waters. The ship navigates through massive icebergs to reach a secret fjord surrounded by towering rock cliffs. Captain Black entertains Mark in a lavishly decorated cavern hidden inside the mountain wall. Despite Black's refined demeanor during dinner, the secluded base proves to be an impenetrable stronghold for a criminal empire.
Part 6
Internal mutiny and restless crew members force Captain Black to abandon his Arctic hideout before winter sets in. Doctor Osbart explains how the ship relies on pressurized gas engines designed by a mute genius, allowing thirty-knot speeds without coal smoke. Mark accepts conditional freedom on deck under a pledge of non-interference as the transformed white vessel heads back into open waters. Brilliant northern lights illuminate their departure from the icy fjord.
Part 7
In London, Mark joins Black aboard a river tender at Tilbury as British authorities close in on the fugitive captain. Trailed by an disguised cruiser across the Atlantic, Black realizes his supply of engine lubricant is running dangerously low. The strain of constant surveillance drives tension higher among the crew as they race toward their main ship. A sudden nighttime engagement brings the confrontation between the raider and naval forces to a head.
Part 8
After the warship sinks in battle, Mark and Captain Black float helplessly on a small raft in the open ocean. Weakened by exposure, Black reveals his past as a impoverished sailor whose family died from an agent's greed. This profound grief transformed him into an enemy of humanity, seeking vengeance against all sea trade. Black dies on the water, leaving Mark with his fortune belt and a sobering understanding of human ruin.
Part 9
High-seas intrigue and technological terror reveal how vengeance fuels ruthlessness across the Atlantic.