The Case Files of Thomas Carney

Tom Carney never thought much about death until it happened. After his face hits the floor and his world fades to black, he opens his eyes in a cramped apartment overlooking the mist-shrouded streets of Afterlife, walks downstairs and enters Afterlife Investigations, a detective agency for dead people with issues. Polly, the agency’s sublimely efficient secretary, hands him his sheet of rules and tells him in no uncertain terms that he is the new principal investigator.

Tom doesn't know why he was chosen, but he can’t get out of Afterlife until he helps the other unfortunate souls stuck there with him. Considering his limited options, he takes the job.