What is the main conflict in Endurance: Shackleton's Incredible Voyage by Alfred Lansing?

Endurance: Shackleton’s Incredible Voyage recreates the epic journey of the Imperial Trans-Antarctic Expedition of 1914 led by Sir Ernest Shackleton as they attempt to cross the continent of Antarctica with a 28 man crew. The ship Endurance frozen into place and eventually crushed by the ice floes of the Wendell Sea sets the stage for Shackleton’s saga of a two year struggle for survival and selfrescue without the loss of a single man.