Efficient, hard-working Dr. Jenny Davin has been chosen to replace new retiree Dr. Habran at the Kennedy Hospital. One night, someone rings the bell of Dr. Davin's office after-hours and she asks her trainee Julien to not open the door since it doesn't seem to be an emergency. The next morning, Police Inspectors Ben Mahmoud and Bercaro require her surveillance tape since a teenager was found dead on the other side of the road and they are investigating what happened. Jenny feels guilty for not opening the door and becomes obsessed to find the teenager's identity. Her investigation affects her relationship with patients that might know something about the unknown girl.