This hour-long young adult series featured the characters from the popular children's books, "The Hardy Boys" and "Nancy Drew," in a weekly mystery. The team of Frank and Joe Hardy alternated with Nancy Drew every other week, with independent storylines. Several episodes featured a larger mystery with a cross-over scheme, involving the investigative talents all three characters.

Episodes:
The Mystery of the Haunted House
The Mystery of Pirate's Cove
The Mystery of Witches' Hollow
The Mystery of the Diamond Triangle
The Disappearing Floor
The Mystery of the Whispering Walls
The Flickering Torch Mystery
A Haunting We Will Go
The Mystery of the Flying Courier
The Mystery of the Fallen Angels
Wipe Out
The Mystery of the Ghostwriter's Cruise
The Mystery of the Jade Kwan Yin
The Mystery of the Solid Gold Kicker