A teenager is spray-painting graffiti at Mulholland Dam in the middle of the night when he is interrupted by an approaching car with its headlights off. He hides.

Later that morning, LAPD Detective Harry Bosch has a nightmare. In the dream, he is back in Vietnam during the war crawling through dark tunnels. Then the phone rings: A dead body has been found in a pipe near Mulholland Dam.

Bosch and his partner, Jerry Edgar, meet at Mulholland Dam. Bosch examines the body pulled out of the pipe: The man has been dead for six to eight hours; he is white, around 40 years old, and unkempt. There is no identification, but there is a heroin shooter’s kit and an injection site in his arm. Most of the cops at the scene are convinced it is an overdose, but Bosch senses something is wrong.

After noticing the dead man’s tattoo, Bosch suddenly recognizes him: Billy Meadows, a “tunnel rat” (17) from Bosch’s unit in Vietnam—the slang term for soldiers who cleared and destroyed enemy tunnels. Bosch hasn’t seen Meadows in 20 years, but about a year ago, they spoke over the phone; Bosch helped Meadows avoid a drug arrest by getting him checked into a Veterans Affairs (VA) clinic instead.