The Africa Shell was never meant to be famous. She was built in the Greenock yards of George Brown & Co on the Clyde, fitted with a Dutch Werkspoor engine from Amsterdam, and sent into service in the late spring of 1939 to do quiet, essential work: carrying oil along the East African coast for the Shell Company of East Africa. By that November she had a crew of 28 under Captain Patrick Dove, and her cargo holds were often filled with Avgas, the high-octane aviation fuel that kept the region's aircraft flying. On the day she was lost she was running empty, sailing in ballast from Quelimane down toward Lourenco Marques, the port that is now Maputo. An unremarkable voyage on an ordinary morning.

Far to the south, a more famous ship was hunting. The Admiral Graf Spee was a Panzerschiff, a fast and heavily armed commerce raider, loosed into the world's shipping lanes after Hitler ordered the German navy to prey on Allied merchant traffic. By mid-November she had already claimed five victims across the Atlantic and into the Indian Ocean, sinking ships and scattering confusion in her wake. The Africa Shell became the sixth. Around mid-morning, roughly ten nautical miles south-southwest of the Cape Zavora lighthouse, the raider spotted the little tanker and fired a single shot across her bow. There was no contest to be had between a coastal oil carrier and one of the most powerful surface raiders afloat. Dove stopped his ship and waited. By the German cruiser's own log, the Africa Shell went down early that afternoon, sent to the bottom of the channel a little after two o'clock.

What followed was almost courteous. A cutter carried a boarding party across, the apology was delivered, and Dove was taken prisoner aboard the Graf Spee while his crew were allowed to make for shore. The captain was furious, not frightened. He protested directly to the raider's commander, Hans Langsdorff, insisting the Africa Shell had been inside Portuguese neutral waters and that sinking her broke international law. Langsdorff was unmoved on the point, but something unusual grew between captor and captive. Over the days that followed, the two men became something close to friends, an odd human warmth aboard a ship built for destruction.

Dove's crew reached Lourenco Marques safely that same day and reported what had happened, but in the telling they made an error that served the raider's purpose perfectly. They described their attacker as a cruiser rather than the Graf Spee, deepening the fog of misinformation the German captain had worked to create. Langsdorff's luck would run out within weeks; cornered at the Battle of the River Plate that December, he scuttled his ship rather than fight on, and soon after took his own life. Dove survived to write a memoir, I Was Graf Spee's Prisoner, in 1940. When the story reached the screen in the 1956 film The Battle of the River Plate, Dove advised on the prison scenes and slipped into the picture himself, playing one of the captives in a story he had truly lived.