Hardy Boys have their holidays at San Francisco with one of their old friend Cody. Cody was doing a business with fossils and he has a shop named Skins and Bones. When they arrived, they heard the trouble faced by Cody in his business and the threats he receives. Soon Hardy Boys were into the case and Dave Cloud; Deb also came to help them out. By the end, it was found that Dave was guilty and they discovered that Dave was Cody’s secret competitor. But Dave was blaming Brando throughout to mislead the case. Brando was a competitor in Cody’s business and was sent to jail for his dishonesty.
But, Joe was kidnapped by Dave and soon, Frank, Cody came to Joe’s rescue. They got Dave arrested with the help of Cody’s father, Sergeant Chang.