Every night at 11:10, a lamp comes on across the courtyard. Every night, a woman sits in its light and watches Mathilde.

A nurse anesthetist on leave since the death of a patient she is held responsible for, Mathilde lives in seclusion in Lyon's Croix-Rousse. Her nights are sleepless, her memory of the fatal night is gone, and her husband fills the pillbox that structures her days every Sunday.

No one believes her when she speaks of the woman at the window. She herself is no longer sure of anything. Until the night the silhouette writes her name in the condensation: don't take any more of the pills.

Who is watching whom? Whom can you trust when you can no longer believe your own eyes? With a too-discreet neighbor, a patient police captain and a secret passage beneath the rooftops of the city, Mathilde must piece together what she was made to forget, and face a truth she may have carried within her all along.

A claustrophobic psychological thriller in which the whole truth fits into fifteen meters of night.