The Cypher Letter: Nick Carter Detective, Book 3 (Unabridged‪)‬

For one instant only, Nick neglected his usual caution. Nick received a blow on the back of his head which sent him stunned and helpless to the floor, face down. When consciousness returned to him, a faint smell of burning wood reached his nostrils. The flat had been set on fire and he was locked in a closet!!!