This is essentially a murder mystery, except it's the victim, who is now inhabiting a very bizarre afterlife, who is trying to figure out who killed him and why. (There is no shortage of people who had reasons to want him dead.) His recall of his life is patchy and memories return rather unpredictably. He's hampered by the fact that the living can't see him, and his ability to communicate with them is limited, as is his ability to control where he goes.

The living are almost entirely unaware that ghosts, demons, and sundry other spirits are everywhere around them, that animals have souls just like humans, these souls can talk to other ghosts; and that there is an afterlife where you have agency and have to make choices on the basis of incomplete data, just as you did in life.