When Mr. Hardy disappears while investigating a mystery surrounding a vacant house rumored to be either haunted or an abode for criminals, the Hardy Boys search for the truth.

After a dying criminal confesses that his loot has been stashed "in the tower," the Hardy boys make an astonishing discovery.

Frank and Joe get mixed up in mystery with the help of a short-wave radio.

Every night water strangely disappears from the new reservoir near Skull Mountain. Frank and Joe join forces with a team of skilled engineers to solve the baffling mystery.

College recruiters are pursuing Bayport High's football star, Terry Golden, and his clique of jocks enjoy basking in his aura of celebrity. When the hazing to become a member goes too far, the Hardy boys begin an investigation. Grades 4-7. (Hardy boys mystery stories ; 170).