Died on a Rainy Sunday — Joan Aiken

A temporary job with Folia Films seems like a lifeline for Jane Drummond. A chance to escape from money worries, a husband who acts like a stranger -- and the unsettling presence of Tom Roland, a one-time colleague to whom she feels uncomfortably attracted. When a local couple, the McGregors, are hired to look after the children and help in the garden, Jane hopes that all will be well. But, though polite, there is something peculiar about them that fills Jane with a formless dread.