In 1947, a dangerous shipping incident ended with an entire train sinking to the depths of Slocan Lake. 75 years later, a diver and his team set out to locate and extract this historic steam locomotive, aided by one of the wreck's living survivors, a 99-year-old brakeman who was on the train that fateful day.

Battling the elements in one of Canada’s deepest lakes, with depths of up to 1000 ft., the grueling expedition tests even the hardiest members of the crew. But as the search goes on, the team stumbles upon a more intimate discovery surrounding the townsfolk who call these remote mountains in British Columbia home.