In World War I London, Myra is an out-of-work American chorus girl making ends meet by picking up men on Waterloo Bridge. During a Zeppelin air raid she meets Roy, a naive young American who enlisted in the Canadian army. They fall for each other, and he tricks her into visiting his family, who live in a country estate outside London, where his stepfather is a retired British Major. However, Myra is reluctant to continue the relationship with Roy because she has not told him about her past.