Teenager Billy Williams and his sister Hannah live with their mother Nancy at a hunting and fishing lodge in Rainbow Country, the popular name of the North Channel area of Lake Huron in Ontario, Canada. The lodge was built by Billy's father Frank, who disappeared two years earlier when his bush plane went down while he was prospecting for gold. At 15, Billy is an accomplished wilderness guide, scuba diver, angler, spelunker, white-water canoeist, photographer, marksman, rock climber, skydiver and electric bass player in his rock group The Thunderbirds. Billy sports a mop of shaggy blond hair and always wears a gold mohair sweater, a GWG denim jacket, beige jeans and Kodiak boots, even on the most sweltering of summer days. Billy's best friend is Pete Gawa, a native Canadian who is equally adept at all the outdoor skills. The inseparable pair experience an endless string of adventures, thwarting the designs of jewel thieves (Mystery at Whaleback Bay), kidnappers (Pursuit Along the Aux Sables), Iron Curtain defectors (Stolen Tugboat), airplane hijackers (Milk Run), the military (Wall of Silence), petty larcenists (Roar of the Hornet), witch doctors (The Return of Eli Rocque) and the Devil himself (Lac du Diable).