Somewhere on the Kent coast is a community of nuns whose Mother Superior is obsessed by her paintings, but as her career as an artist improves to previously unanticipated successes so she slowly succumbs to cancer, creating a strange power vacuum in the order. Then other nuns start to die in expected but plausible, horrific farming accidents. Detective Inspector Vail is bewildered despite many hours of reading the ACPO manual that invites him to "Think MURDER".