By Ann Hornaday, The Washington Post “My Cousin Rachel” swirls around a deliciously twisty premise: On a sprawling Cornwall estate in the 19th century, a young heir-to-be, Philip Ashley, discovers that his beloved guardian, Ambrose, has died mysteriously while taking the healing sun in Italy. Philip immediately suspects foul play at the hand of the woman Ambrose married during his sojourn, a distant cousin named Rachel, and determines to take revenge — a plot slightly complicated by the fact that, when she unexpectedly fetches up in England, he falls hopelessly in love with her. The setup is so irresistible that it’s been done before: Back in the 1950s, Richard Burton and Olivia de Havilland played Philip and Rachel in a production that is memorable mostly for its windswept atmosphere and Burton’s U.S.