It's the end of the season in Les Cimes, holidaymakers leave, the snow melts... revealing the corpse of a murdered woman in a macabre setting. Swiss detective Sterenn Peiry is in charge of the case, supported by French investigator Lyes Bouaouni as a body in similar condition has been found on the other side of the border. As the mystery deepens, the investigator discovers that her son accidentally killed his girlfriend, turning her life upside down. How far should she go to protect her son?