Now back in San Francisco after their holiday in New York, Nick and Nora find themselves trying to solve another mystery. It's New Year's Eve and they are summoned to dinner at Nora's elderly, and very aristocratic, family. There they find that cousin Thelma's husband Charles has been missing for three days. Nick reluctantly agrees to look for him but the case takes a twist when Charles is shot and Thelma is accused of murder. Several other murders occur but eventually Nick gathers everyone into the same room to reveal the identity of the killer.