Riddle Ring is a romantic mystery novel set in Paris during the late 19th century. It follows the story of Jim Conrad, a man who discovers an unusual gold ring while visiting the city. The ring has a strange inscription and he soon learns that it is connected to a tragic love story. As Jim investigates the ring's origins, he becomes entangled in a web of intrigue and danger. The novel is full of suspense and keeps the reader guessing until the very end.