In a flashback, late-Victorian beauty Ruby, a divorcee with a shady past, calculatingly marries rich Egyptologist Nigel, who installs her at his Cairo estate while he digs for mummies. Bored, Ruby undertakes to recover a friend's letters from Baroudi. But when she meets the blackmailer, mutual attraction leads to an affair. As Ruby gets in deeper, she finds Baroudi is even more unscrupulous than she dreamed.