The Three investigators mystery series

While attending a week-long family reunion on a California island, the Three Investigators find their photographs of the event hold an inordinate interest for someone else, and receive clues to that unknown identity from both an ancient and a modern boating accident.

Three young detectives become involved in mysteries related to the disappearance of an ancient Japanese jeweled belt from a museum exhibit and the strange antics of a group of gnomes around an elderly woman's house.

Three young detectives undertake a case involving an Egyptian mummy that whispers, but only to one man.

The three investigators, attempting to rescue a beached whale, end up searching for sunken treasure.

Three young detectives try to trap an invisible vandal who has been breaking car windows all over town.

A wallet dropped by a scar-faced beggar sets the three investigators on the trail of bank robbers.