Told in part by way of some counselling sessions with "Dr. Bormans" (Nicole Garcia) we meet divorcee "Claire" (Juliette Binoche). A university lecturer with two teenage sons, she has an affair with "Ludo" (Guillaume Gouix) but a strange call makes her suspect he's not so trustworthy. A little online searching introduces her to his flatmate "Alex" (François Civil) who initially she wants to use to get to her beau, but gradually - and impersonating a woman half her age - she befriends him, they chat on the phone and a relationship stats to develop. Thing is, with her whole persona based on lies ...