"A story about a god." That's how Northrop Frye defined myth. But the Greek myth of Caenis and Caeneus is less about the god Poseidon than about his paramour, the nymph Caenis, a "lesser" god whose favour he grants to become a man. As Caeneus, perceived male, she fights valiantly in war and is later elected king. This story takes up only a few sentences in Robert Graves's The Greek Myths. In Caenis and Caeneus, Paul Matthew St. Pierre writes it large, shifting the setting from Ancient Greece to the First World War and making the nymph a Birmingham chambermaid, Celia Richards, who becomes a man when she impersonates her twin, Cedric, a deserter from the Brummagem Guard, and goes off to war in his place. In France, she distinguishes herself in battle and daring reconnaissance and search and destroy missions behind enemy lines, a woman taken for a man not through magic, the hand of god, or a transformation, but through performance, her ingenious portrayal of Cedric to save him from the gallows. Celia Richards is a new kind of war hero, a woman capable of doing all a man can do, only better. She makes the supreme sacrifice, giving up her life for her brother, heeding the call of king and country.