It is 1977, and a spring hiker on Canada's Cape Breton Island has discovered a strange-looking installation hidden in the forest, on an oceanside cliff. Word of her discovery makes its circuitous way to military intelligence and the RCMP Security Service, where it sets off alarm bells, and Constable Alex Houston and her dog Silver are sent in. They are a unique team since few people know that Alex is the first woman Mountie and Silver, an Alaskan Malamute, looks nothing like a police dog. As they investigate, a technological curiosity from the Second World War turns out to be the centrepiece of something very current, and sinister. As Alex and Silver investigate, this time they will need to be ... indestructible.