When Jack Haines reports a break-in at his greenhouse, the motive of the intruder is unclear. Other than the destruction of some expensive orchids, no damage has been done and nothing seems to be missing. But Detectives Sloan and Crosby sense something sinister, and soon their suspicions are confirmed. Similar reports are multiplying and sabotage is the word on everyone's lips.

The pair are drawn into an equally perplexing case when the mysterious Miss Enid Maude Osgathorp goes missing. It soon becomes clear that the cases are linked, but will this provide the clues necessary to solve the mystery? Detectives Sloan and Crosby aim to find out . . .