The stooges apply for job as 'Yard Men' at Scotland Yard, thinking they'll become detectives, but instead wind up as gardeners. When they learn that detectives are need to guard a Scottish castle where valuables have been disappearing, they masquerades as Scotsmen to get the job. After a spooky night in the castle, the boys expose the servants as the crooks.

In 17th-century England, Charles II, the rightful heir to the kingdom, is driven from his country by militants working for rogue leader Oliver Cromwell. Charles ends up in the Netherlands, where he falls for local beauty Katie and spends his days happily in the quiet countryside. Unfortunately, Cromwell's associate Col. Ingram and his men track Charles down, and the would-be monarch must resort to swashbuckling his way to freedom.

When Ivy, an Edwardian belle, begins to like Miles, a wealthy gentleman, she is unsure of what to do with her husband, Jervis, and her lover, Dr. Roger. She then hatches a plan to get rid of them both.

Holmes and Watson board a passenger train bound from London to Edinburgh, to guard the Star of Rhodesia, an enormous diamond worth a fortune belonging to an elderly woman of wealth; but within the first hour of the trip, the woman's son is murdered and the diamond stolen and any of the passengers in their car could be the killer thief.

When composer George Harvey Bone wakes with no memory of the previous night and a bloody knife in his pocket, he worries that he has committed a crime. On the advice of Dr. Middleton, Bone agrees to relax, going to a music performance by singer Netta Longdon. Riveted by Netta, Bone agrees to write songs for her rather than his own concerto. However, Bone soon grows jealous of Netta and worries about controlling himself during his spells.

Genial shopkeeper Philip has to endure the constant nagging of a shrewish wife while he secretly yearns for a pretty young stenographer. When the henpecking gets to be too much, Philip murders his wife and manages to make her death look like an accident. A ruthless blackmailer and a low-key detective both discover Philip's secret, and he has to decide which of them poses the more dangerous threat.

German Julius Reuter sends 19th-century news by carrier pigeon and then by wire, founding a news agency.

The first of eight "Three Mesquiteers" Westerns to star John Wayne.