Deadly Inheritance — Janet Laurence

Accompanying American heiress Belle Seldon on a visit to her ancestral family home in Somerset, Ursula Grandison soon discovers that the decaying stately Mountstanton House and its inhabitants has many secrets, including a crumbling marriage and a missing dowry. When Ursula discovers the drowned body of the nurserymaid, she is determined to reveal the killer and, in doing so, reveals a tangled web of deception and adultery that threatens the reputation of the house of Mountstanton.