Waterloo Bridge tells the story of a dancer and an officer who meet in a chance encounter on Waterloo Bridge. This initial encounter occurs during an air raid in World War I. But because of the Hays Code, which had not been in effect when the 1931 film version was made, the plot of the 1940 version had to be changed and somewhat sanitized. In the original play and film, Myra is an ordinary chorus girl of easy virtue, and Roy is too naive to realize this until near the end. In the 1940 version, Myra is a ballerina in a prestigious dance company, who descends into prostitution after mistakenly believing that Roy has been killed. In the first film, Myra is accidentally killed; in the 1940 version, she commits suicide in order not to involve Roy in a scandal.