October 1908. McMurdo Sound, Antarctica. Forced by ice conditions to break an agreement with Scott, Shackleton has returned to Ross Island. From the expedition's base at Cape Royds an attempt to reach the South Pole is about to begin. The logistical setback has severely limited their plans.

December 1916. After the loss of 'Endurance', Shackleton and his 27 men endeavour to cross the frozen Weddell Sea. Land lies 350 miles away, and as they drift helplessly northwards they know that soon the ice will break beneath them.