The Deep Pool — Jane Blackmore

When Emma came to the secluded country home of Robin Hawkins to be governess to his daughter, she was intrigued and repelled by his strange household. There was his wife Maud, who took to her bed and brooded over life and death. There was Torquil, a sinister young man who had a disquieting influence over everyone who knew him. And there was the mystery of the deep pool, which plunged them all into an abyss of guilt and recrimination.

It was not only the envenomed atmosphere that disturbed Emma, for she soon found herself unwillingly drawn into the arms of Robin Hawkins. But their clandestine love was overshadowed by the unresolved past, and Emma found herself haunted by Robin's mercurial and violent temper.

Caught up in their tangled affairs, Emma's romantic obsession forced her to pry into a tragedy that threatened her reason and, finally, her very life.