During World War I, an illegitimate son of the German Kaiser, who had been raised in the US--and is a double for the Kaiser's son, the Crown Prince--is sent to Germany as a spy in order to kill both the Kaiser and his son.

Based on an international scandal that hit prewar France, when the editor of the Paris daily LE FIGARO, Gaston Calmette was shot to death by Madame Caillaux, wife of the Minister of Finance for his exposè of her husband's traitorous activities on behalf of Germany.

Annette Kellerman, the Australian swimming star of the early 1900s, made a number of films, most of them in the 1910s, which displayed her athletic skills. Most of these films were underwater fantasies, and this one was no exception. Here, Kellerman is Merilla, a mermaid who is the "Queen of the Sea." Not satisfied with being a mermaid, she wants a mortal human body with an immortal soul. She discovers she can achieve this if she saves four human lives.

Charles Trevor is a young chap just out of college, who is put to work on a daily newspaper and at once starts to lead a life of adventure and romance. A German spy and a maiden in distress cross his path the first day and, before the end of the story, he has landed a big scoop for his paper, put the German in jail and married the girl.