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 Mystery of a Cruel Game Jupiter, Pete and Bob decided to take part in a war game to test their strength and once again prove to themselves, that they can withstand any difficulties. However, the friends needed not only courage, but also real weapons: the game turned out to be a cover for a crime.