It's 1916 and World War 1 is fully under way. Recruiting stations are popping up in small towns throughout Australia. The Hoagland family however, has no interest. Following the footsteps of their father, three brothers learn the job of being hard rock gold miners on their old man's gold claim situated just outside of Bendigo in regional Victoria. Things go well for them until tragedy splits the family apart and suddenly joining the 175th tunnelling company seems like a good idea to escape the pain and anger that everyone feels. Over the pond in France, the diggers go to work underground in the Vimy sector as they risk life and limb while expanding the subways and dugouts that are already there. The sappers have a deadline and objectives that must be met before the Canadians arrive in October of 1916. Working day and night is hard on everyone as the Germans try to find their tunnels and blow them up. Will the Hoagland's get through the danger? How are the families coping while they're away from them? Besides the Huns what other dangers are to be found beneath Vimy Ridge?