"One thousand feet plus. If that dial is right, we passed the theoretical implosion point - where the hull should have collapsed - fifty feet ago. At the present moment she's being subjected to well over a million tons of pressure."

The captain's glacial calm was staggering. His runaway craft, the Dolphin, the U.S. Navy's most powerful nuclear submarine, was sinking into the realms of unknown. Aboard her, a member of his crew had just been murdered and the killer was at large.
Above all, he suspected that Carpenter, the mysterious "passenger", who claimed to be a British secret agent, was a fluent liar, with a more sinister motive than the rescue of survivors from a burnt-out Arctic weather station called Zebra. In fact Carpenter had boarded the Dolphin on false pretences and later, when challenged to give an explanation, he threatened the captain with a gun!
"Ice Station Zebra" packs the screwed-up tension of a spy thriller into an entirely new locale - the crammed confines of a metal tomb trapped beneath the compacted ice-mass that covers the top of the world. Author Alistair MacLean, who admits to his fascination for the lonely immensity of these freezing Arctic wastes, has written a story terrifying in its topicality in which the pace moves with the explosive force of a torpedo and the excitement glows white-hot in its intensity.