Gustave Klopp suffers from narcolepsy, he can fall asleep everwhere at anytime whithout warning. Living a simple life with his wife Pam and his best friend Lenny Bar, Gus decides…

Joseph Rouletabille (Bruno Podalydès), a reporter for a local newspaper, investigates the attempted killing of Mathilde Stangerson (Sabine Azéma), who uses the yellow room of the title as her bedroom….