On a short flight to Catalina Island off the California coast, Roswell T. Forrest gets sick. When he is found dead upon landing, it appears to be murder to fellow passenger Hildegarde Withers, but she has a tough time convincing local police chief Britt and coroner Dr. O'Rourke.
When she contacts her friend, Police Inspector Oscar Piper, for more information about the deceased, he recognizes the name: the man was a vital witness in a case against a crime syndicate and had a price on his head of $10,000. He flies from New York to assist her in investigating the case and protect her from mob retribution.
When he arrives, the pair argue over which of the people aboard the plane is the killer:
Joseph B. Tate, a famous Hollywood director,
struggling actress Phyllis La Font, who is angling for a part in Tate's next movie,
honeymooners Kay and Marvin Deving,
Captain Beegle, a retired, self-confessed former rum runner, and
pilots Dick French and Madden.
Withers suspects poisoning – Forrest had been given a drink, a cigarette, and even a dose of smelling salts by Withers herself – but before this can be confirmed, the body is stolen. While Piper questions those involved, Withers discovers that McArthur, the gangster who had offered the reward for Forrest's death, has registered at the hotel under the flimsy alias of Arthur Mack. When she eavesdrops on his telephone conversation, she learns that he will be leaving an envelope for someone. She purloins it from the mailbox and finds $10,000 inside.
More murders occur. Marvin Deving is shot and killed just before he can reveal some information to Piper. Meanwhile, Withers and Piper learn that the first victim was not Forrest, but his bodyguard Tom Kelsey. He and the real Forrest had switched identities.
After McArthur confronts Withers at gunpoint, trussing her up and putting her in the closet, from which she is rescued by Piper, McArthur is also found dead. Although it was staged to look like a suicide, Withers notices that the pistol in his hand is not his own.
When an employee complains that the fish in the hotel pond are all dead, Withers finds a pack of cigarettes discarded nearby; one of the cigarettes had fallen into the water, poisoning and killing the fish. With the murder weapon found, all the pieces come together. Withers takes Piper to see the grieving Kay. She offers the widow a cigarette, then casually mentions where she got it. When Kay refuses to smoke it, Withers tells Piper that McArthur's gun must be in the room. Kay pulls it out and tells them that she will have to kill them both now, but Withers manages to distract her, enabling Piper to disarm her. It turns out that the Devings thought they had been doublecrossed by McArthur when they did not receive their reward for committing murder, unaware that Withers had taken it. When Marvin tried to betray McArthur in return, he was killed by his employer, and Kay then killed McArthur.
Gleason played the role of Inspector Piper in all 6 films in the series.
Production
The working title for Murder on a Honeymoon was Puzzle of the Pepper Tree,[2] which was the title of the 1933 Stuart Palmer novel on which it was based.[3]
Some scenes for the film were shot on Santa Catalina Island, a well-known resort 26 miles off the California coast.[2]
A Douglas Dolphin twin-engine flying boat appears early in the movie; the characters fly on it to get to Catalina Island, and the (first) murder takes place on it.
