50-year-old surgeon Antoine Fregoli awakens one morning with the sudden feeling that his wife Elizabeth is someone else. Existential doubt leads him into an obsessive search for truth. How far will Antoine go to find his real wife Elizabeth? And what is he going to do with the other? Through Antoine's story, the director plunges us into a complex and subtle search of identity which brings into question the couple, our knowledge of the other and of ourselves.