In 1940 the Nazis hoped to cripple the British war effort by blockading Swedish cargo ships containing ball bearings, steel and tools vital for making arms and equipment. In desperation the newly formed SOE was asked to rescue these badly needed supplies and a daring escapade was dreamt, which involved sneaking in under the Germans' noses to steal the ships. It was a dangerous mission and the 147 men involved knew there was a high chance they would not come home. The terrifying operation to rescue cargoes of ball bearings in clunky transport ships, while trying to outrun the Luftwaffe and German navy, had never been attempted before. It was a success that was never repeated. Making use of newly released files from the National Archives, Sophie Jackson tells the story of a forgotten adventure that saved Britain and her troops from certain defeat, all because of brave men willing to sacrifice their lives for millions of small balls of steel.