Death is discovered on an idyllic southern California island when feisty British gossip columnist Tosca Trevant is banished to the U.S. at the request of Buckingham Palace. Idly snooping out of sheer boredom, she stumbles across what she believes to be human remains in a recently widowed music professor's rock garden. Tosca asks a retired U.S. Secret Service agent for help, and by solving the riddle of a coded music score, the two sleuths bring a serial killer to an unexpected end.