While vacationing at a family reunion in Alberta, Holly Brannigan and her three friends, Bonnie Tilson, Paul Castles, and Ted Lumley, find themselves caught up in some local scullduggery. A young swimming coach has disappeared, and the local campground is robbed in the middle of the night. When they discover that the robbers might be scuba divers, the young sleuths agree to use their amateur scuba diving skills to help the police. Holly and her friends call for volunteers to form a search and rescue party to search for the robbers and the missing coach. Their adventure takes them into the ice-cold waters of Crowsnest Lake, where they discover a train wreck that had been buried in the lake for almost a century, as well as some very unusual discoveries in a cave. They also explore abandoned derelict cabins and an abandoned mine on Turtle Mountain. Along the way, they meet interesting and eccentric characters who aid in their quest and share the exciting history of the area. Will the brave sleuths be successful? Will they find the missing coach before it’s too late? Join Holly and her friends on one of their most exciting cases yet!