A 15 episode serial in which boy detectives Frank and Joe Hardy try to solve the mystery of a haunted farm where the farmer has died and left no one to care for his livestock. A ghost assists them to prevent the acceptance of a false inheritance claim.
Frank and Joe Hardy are the sons of Fenton Hardy, a famous private detective. Finding everyday life at home in Bayport dull, the boys hope their father will let them work on one of his cases. Disappointed when he tells them his work is too dangerous for children, they are more determined than ever to follow in their dad's footsteps, and solve mysteries.