The three detectives are his young friends Bob Andrews, Pete Crenshaw and Jupiter Jones. They live in a town near Hollywood. Their stronghold is a salvage warehouse, their headquarters is an old caravan in which they have equipped a crime laboratory. Their agency "Three Detectives" reveals any secrets, riddles and puzzles. Friends-detectives boldly take on the most important and complicated cases and bring them to the end with honor.

The Secret of the Ominous Mines An abandoned mine hides a terrible secret: a dead man is waiting in the wings. A charming woman is in mortal danger. To save her, three detectives will have to go down into a dark and dangerous labyrinth.