Lilian (Jodie Foster) is an American psychiatrist living and working in France. Although she's American, she's lived in France for many years and speaks French fluently with hardly a sign of an accent. She begins to have problems with her patients — one man is incensed that after years of being in therapy with Lilian to stop smoking, he spent an hour with a hypnotist, and claims he's been cured. He wants to sue Lilian for all the thousands of Euros he's paid her with no results.

Then Lilian learns that Paula, another one of her patients, has committed suicide. Lilian begins to believe Paula may have been murdered. Lilian gets her ex-husband Gabriel (Daniel Auteuil) involved to help her determine what happened. As they begin sleuthing, following Paula's husband and daughter, things get dangerous.