PERCIVAL GREY is a failed Shakespearean actor who, with his gormless son, Larry, sets up a Detective Agency. Their Office is above a Veterinary Surgeons from whence Larry obtains a stray Irish Wolfhound, Fritz. The pair make a hash of almost every case they take on, straining the patience of the local Police, but during one of their investigations they unwittingly uncover a trade in illegal animal skins. Their probing results in the murder of a young prostitute. A very bossy lady, Doris, persuades Percy to employ her as his Secretary. His housekeeper's estranged son turns up unexpectedly. Is he a spy for the gang? Despite threats, the pair persist placing our hero in a dangerous situation and Fritz finally earns his keep.