Established after World War I by the Royal Australian Navy, the Coast Watchers were a loose organisation of several hundred European settlers, missionaries, patrol officers and planters living in British and Australian Pacific Island territories whose job it was to observe and report on the enemy. They were mostly all unpaid volunteers whose job it was simply to observe and report on foreign shipping and aeroplane movements.

It was never envisaged that the Coast Watchers would do any fighting, nor operate inside enemy-occupied territory. But when World War II came to the Pacific, that is exactly what they ended up doing, becoming, in effect, Australia's secret army. Fully cognisant of their fate should they be caught, they nonetheless battled not just the enemy, but constant exhaustion, tropical disease, and the ever-present spectre of capture, torture and death.

Without the Coast Watchers and the crucial intelligence they provided, key moments in the war could have turned out very differently. This is the story of these unsung heroes who risked their lives - and sometimes lost them - in the service of their country.