Pragmatic Sgt. Natalie Zimmerman of the LAPD is paired with Sgt. Valnikov, a romantic detective of Russian origin who is going through a midlife crisis and driven to drink by the pressures of his job. Together they investigate the kidnapping of a Beverly Hills socialite's valuable pet dog. It was carried out by sleazy gambler Philo Skinner, who runs a beauty parlor for pets and is desperately in need of cash to cancel his debts.
The teaming of the officers not only helps Valnikov to put himself together, but the pair also falls in love. While containing more humorous elements than most of Joseph Wambaugh's stories, it continues to explore Wambaugh's common theme of the psychological burdens of police work.
A comedic highlight of the film is a slow-motion chase sequence through a very messy dog kennel.
The title of the film comes from a phrase used by Natalie. The term "black marble" is synonymous to choosing the short straw or having bad luck. She states that she is always picking the black marble and does not want to anymore. She initially considers Valnikov a "black marble," but ultimately no longer believes this to be true.