"My Cousin Rachel" by Daphne du Maurier
Orphaned at an early age, Philip Ashley is raised by his benevolent older cousin, Ambrose. Resolutely single, Ambrose delights in Philip as his heir, a man who will love his grand home as much as he does himself. But the cosy world the two construct is shattered when Ambrose sets off on a trip to Florence. There he falls in love and marries - and there he dies suddenly.
In almost no time at all, the new widow - Philip's cousin Rachel - turns up in England. Despite himself, Philip is drawn to this beautiful, sophisticated, mysterious woman like a moth to the flame.
And yet ...might she have had a hand in Ambrose's death?