Private Investigator Agnes Trout is settling back into her New York apartment after resolving a case in England and Wales with her new partner and colleague, Jonathan Black. Their professional and personal relationship has progressed comfortably and easily over time in spite of Agnes' natural caution and desire for independence.
At home, telephone messages indicate that there will be more demands for her expertise. The first of these is a mysterious message from a frightened man who asks for her help in identifying what he is convinced is a surveillance team that is constantly watching and threatening him. Another message was from her mother, who lives in Florida. She left a cryptic message about the occurrences of several deaths in her retirement community, suggesting some kind of mystery about them.
Agnes will now have the chance to visit her parents and also introduce them to Jonathan. She and Jonathan are about to pit their skills, acumen, and intuition against cunning and supremely arrogant adversaries who have no compunction about the lethal treatment of others.