Jerry Mulligan is an exuberant American expatriate in Paris trying to make a reputation as a painter. His friend Adam is a struggling concert pianist who's a long time associate of a famous French singer, Henri Baurel. A lonely society woman, Milo Roberts, takes Jerry under her wing and supports him, but is interested in more than his art.

In 1903, Doctor Huntington Bailey meets a friendly older lady during a train trip. She tells him that she is going to visit her brother Nick and his lovely young wife Allida. Once in New York, Bailey hears that his train companion suddenly died. Shortly afterward, he meets the strange couple and gets suspicious of Nick's treatment of his wife.