[1] The novel is set during World War II in Sumatra, Dutch East Indies.

The term "foreign legion" does not refer to the French Foreign Legion, but is the name given in the book to a small international force (including Tarzan) fighting the Empire of Japan.

While serving in the Royal Air Force under his civilian name of John Clayton, Tarzan is shot down over the island of Sumatra in the Japanese-occupied Dutch East Indies.

He uses his jungle survival skills to save his comrades-in-arms, and they fight the Japanese while seeking escape from enemy territory.

[2] According to Tarzan Alive, Philip José Farmer's study of the ape man's life and career, the incident related occurred in January 1912.