Half an hour ago you received an unusual telephone call at the police station. The caller reported excitedly that there had been a murder in the House of the Grays. In the same breath, however, the caller said that it cannot possibly have happened. You are now standing alone in front of the House of the Grays.
Actually, your boss, Inspector Paddocks, is usually responsible for things like this. He would never let you investigate a murder. (Particularly since it's the first murder case in this area for years.) But this evening Paddocks was not there. He is visiting his parents-in-law in Cornwall and it will take a few hours before he gets back. So you set out alone.
To track down a murderer.