In WWI London, out-of-work American chorus girl Myra makes ends meet by picking up men on Waterloo Bridge. During a Zeppelin air raid, she meets Roy, a naive young Yank who enlisted in the Canadian army. After they fall for each other, Roy tricks Myra into visiting his family, who live in a country estate outside London, his mother having remarried to a retired British Major. Myra is reluctant to continue the relationship with Roy, he not aware of her past.