San Francisco, 1948. Frank Swiver is a down and out private eye with a taste for wine and women, not necessarily in that order. Frank readily accepts an unexpected job offer from well-known wine connoisseur General Lloyd F. Thursby to find the murderer of his very good friend, Rusty O'Callaghan. Invited to attend an exclusive wine tasting on Thursby's private rail car, Frank takes along his secretary-come-lover Vera Peregrino to complete his cover. Thursby entices his guests with the promise of a taste of a rare California wine: the Ravensridge Blackbird Noir. All does not go to plan, though, when General Thursby is murdered before the wine tasting has even begun. Frank is caught up in the allure of his former lover, Cicilia, who also happens to be the dead Rusty O'Callaghan's widow. Locked into the private carriage until the passengers reach their destination, the guests proceed to pull some corks and theorize who among them could be the killer.
When Vera is arrested for Thursby's murder, Frank must change his perceptions and find the real killer, or lose both Cici and Vera . . . and maybe even his life.