The small detectives Theo and Button continue to investigate hidden secrets of artworks of the most well-known Latvian artists. This time it is Niklāvs Strunke and his painting “A Man who Enters the Room” that pull the detectives into the vortex of adventures.
For several weeks newspapers are reporting of a terror that has seized Rigans: a strange man in grey coat has appeared in the city, who goes through the walls of houses like a ghost.
Detective Theo starts to investigate the case and meets the Grey Man face to face. Following the smell of dust and the call of the Grey Man “Čau!”, Theo with his partner Button and her fat dachshund Comma go into the streets of Riga to find out whether art can rally step out of the dust-covered painting frames and take a walk in the streets of today’s city. The art detectives will discover the secret of the Grey Man and will find out who introduced into Latvian the Italian greeting “Ciao!” (Čau!)