The Endurance, the enormous wooden ship commanded by Sir Ernest Shackleton during his 1915 Imperial Trans-Antarctic Expedition, is being crushed by millions of tons of ice in the Antarctic’s frozen-over Weddell Sea as the book opens. Frank Wild, the second-in-command, realizes that the main beams will soon succumb to the pressure, and orders sailors Walter How and William Bakewell to prepare to evacuate. The engineers have made heroic efforts for the preceding 72 hours to maintain steam in the boilers in order to power the engine room pumps. They were horribly aware of the condition of the ship, as “her sides—though they were 2 feet thick in most places—bowed inward 6 inches under the pressure” (4).

The men maintain a preternatural calm as they prepare to leave the precarious shelter of the sinking shift for the -8 ½ degree ice. The crew rig a makeshift canvas chute to the port rail and slide each of the 49 huskies to their colleagues on the ice below. While the sky is clear at dusk, the ice floes move together “like an enormous jigsaw puzzle” (5), skewing the ship and working to sever her in half. The men are struck “by the way the ship behaved like a giant beast in its death agonies” (7).