The novel is set in 1951,[3] and the protagonist is ambitious LAPD Officer Fred Underhill, a young cop on the rise, working out of the Wilshire station.

He covers the beat with his partner Herbert Lawton "Wacky" Walker, a World War II veteran with a Medal of Honor, a drinking problem, and an obsession with death.

The trail leads to other murders, new and old, and a beautiful crippled district attorney named Lorna Weinberg.

Several characters from Ellroy's later L.A. Quartet series first appear here, including police lieutenant Dudley Smith, Michael Breuning, and Richard Carlisle.

Clandestine earned Ellroy an Edgar Award nomination from Mystery Writers of America in 1982.