Gus needs help! Great Uncle Horatio has died and left him a fortune. At least, Gus thinks there's a fortune, in something called the Fiery Eye. But all he has to start with is a mysterious message from Horatio, a message full of riddles. It's a perfect case for The Three Investigators, who are very good at solving riddles. But, so, unfortunately, are some other people. The young detectives find themselves in a desperate race, with a sinister bunch of fortune hunters hot on their heels!