In 1942 a Catalina crew of 210 Squadron, based at Sullom Voe in the Shetlands, was selected to carry out a series of highly secret operations, including a flight to the North Pole. The sorties were associated with a Norwegian expedition from Britain to Spitsbergen, to deny the use of the territory to the enemy. The flights made by the crew were frequently over twenty-four hours in length and reached the limits of human endurance, in conditions of extreme cold. Later, the squadron was detached to North Russia, to provide cover for the convoys taking vital supplies to the Allies on the Eastern Front. The navigator of the crew, Ernest Schofield, retained logs of most of these sorties. Together with other survivors of the crew, accounts from German sources and research carried out by Roy Conyers Nesbit, he recreated these little-known events, in detailed and accurate narrative that ends in tragedy.