A Russian woman named Irena (Xenia Rappoport) calculatedly insinuates herself into the lives of a young, affluent Italian family. Stopping at nothing to become the couple's trusted maid and the beloved nanny to their fragile young daughter (Clara Dossena), Irena risks everything in her quest to uncover the truth about the family. Like an intricately constructed jigsaw puzzle, THE UNKNOWN WOMAN reveals piece by piece the enigma of Irena's past.