This book follows Tarzan and the Jewels of Opar chronologically. The action is set during World War I. While away from his plantation home in East Africa, invading German troops destroy it and kill his wife Jane and the Waziri warrior Wasimbu who is left crucified. Tarzan's search for vengeance is filled with much danger, many fierce fights and tons of action as he becomes active in the war on the British side. This is really just the start of the exciting adventures portrayed in this book.