Two resourceful teenage brothers who admire their detective father set out from their coastal town to aid him and soon become embroiled in a case involving a long-hidden hoard and a suspicious old tower. They motor through dangerous roads, follow physical clues such as tire and foot tracks, interview witnesses, and trail several suspects while managing close calls and clever traps. Their methodical searches, a dramatic tower-room discovery, and a confession lead to arrests and recovery of the stolen treasure, with the brothers proving their investigative instincts and courage.