Under the Polar Ice-Cap ….The atomic submarine ‘Dolphin’ has impossible orders: to sail beneath the ice-floes of the Arctic Ocean to locate and rescue the men of weather-station Zebra, gutted by fire and drifting with the ice-pack somewhere north of the Arctic Circle.But the orders do not say what the ‘Dolphin’ will find if she succeeds that the fire at Ice Station Zebra was sabotage, and that one of the survivors is a killer