Finally, a new case for "The Three Investigators"!

Justus, Peter and Bob are back and better than ever.

It's Justus' birthday, and not by chance, a strange video falls into the hands of the friends. On it is footage of Justus' parents, who died many years ago, trying to give their son the answer to an especially difficult riddle. Of course, the boys immediately follow the clues to the abandoned - and seemingly haunted - house of a mad professor. With the town Sherriff getting in the way, and the threat of ghosts upon them, can the friends solve the riddle left to them by Justus' parents?

This sounds like another case for The Three Investigators.