DC private investigator Al Pennyback is hired to prove that the client of his friend Quincy Chang didn't shoot his wife, who is lying in a coma in a hospital bed. Trusting his friend, Al sets out to find who did the crime. He finds a long list of suspects, including the victim's self-indulgent daughter, but can't find a 'smoking gun' to be able to pin the deed on any of them. When the injured woman comes out of her coma, she adds a complication by first saying that she shot herself, and then that she can remember nothing of what happened.
This mystery, set in Washington, DC, moves from one neighborhood to another, from the working class suburbs of Maryland to the high-rent Watergate, and Al finds himself with more questions than answers. He has a crime, with lots of motive, but is hard pressed to show opportunity, and moreover, the gun used in the crime; which belonged to the husband who was in the house at the time; has disappeared.
After following one blind alley after another, Al stumbles across the wannabe killer in the unlikeliest of ways, and almost becomes a victim himself.