A trip to Niagara Falls lands The Scooby-Doo Detectives in the middle of a spooky mystery involving a mysterious sanitarium run by Dr. Tewkesbury, and the ghost of Dr. Coffin, a mad doctor (for whom Tewkesbury previously worked). A wild chase through the sanitarium, the lab and the X-ray room leads Scooby-Doo & company to a secret tunnel and underground cave. There they discover that the “ghostly” Dr. Coffin, whom they previously encountered disguised as Officer Oldfield of The Canadian Border Patrol, is really the ringleader of a gold robbery that’d occurred recently in Montreal. The “corpses” apparently disappearing from the sanitarium in ambulances are really lumps of gold bullion. Scooby-Doo proves himself a real “Fred Astaire” by dancing with Daphne Blake to celebrate, a talent he’d displayed earlier with Cuddles and Snookums, a couple of guard dogs under one of the mad Dr. Coffin’s spells.