Following a painful divorce, Lara, a quiet woman working for the European Court of Justice, finds a new lease on life through a passionate, intensely physical relationship with Joakim, an enigmatic and alluring stranger. However, her newfound domestic bliss turns into a paranoid nightmare when a series of gruesome murders occurs in the dark, rocky valley of the Péitrusse river in Luxembourg City. When the local police begin to suspect Joakim of being the serial killer, Lara is pulled into a suffocating vortex of doubt and obsession, forcing her to investigate her lover's shadowy past while wrestling with severe guilt over an uncovered history of marital infidelity and toxic family secrets.