Frank and Luella are employed by Jonathan Skylark to investigate the death of his wife Ophelia at a river party, promoting their failing business and her 40th birthday, by drowning in the River Avon. After an open verdict by the coroner a (pound) 500,000 insurance policy pay out rests on the investigation. The party had been organised by business partner Finty Lee-Jones and was attended among others by Ophelia's stepson, her best friend society photographer Vanessa-Rose and suspected lover Antonio Da Costa. Ophelia had been spending the companies money leading to a heated row with her husband the night of her death as had the stepson who sold Ophelia's expensive watch after finding it by the river. Frank and Luella discover Ophelia had a morbid fear of water and a previous drowning of a 14 year old girl 25 years earlier is linked by an identical tattoo on Ophelia and the 14 year old girl's back.