The Sinister Sign Post (The Hardy Boys Mystery Stories Book 15)

iii, [1], 215, [3] pp. 8vo. #15 in The Hardy Boys Mystery series. "In one of the most dangerous and intriguing cases of their careers, Frank and Joe Hardy help their father investigate a series of mysterious car accidents. Each of the drivers had seen a signpost marked DANGER shortly before his accident. The young detectives investigate, only to discover that the signposts have vanished. The attempted theft of a secret experimental motor and the kidnapping of a famous race horse are part of this thrilling case, which proves to be as sinister as the signposts themselves."