A high-society couple are violently attacked at home. The investigation leads Cherif and Briard to a centre for the deaf and hard-of-hearing, where they find that silence really is golden!

Still trying to recover his memory, Cherif is admitted to a rest home for police officers, where he meets Elodie Mansard. Receiving treatment for psychological problems, she claims that she has been the victim of several murder attempts since arriving. Only Cherif believes her and decides to investigate.