Unexplained laughter

the long version

"Recovering from a love affair gone wrong, Lydia retreats to the Welsh countryside, leaving behind her sophisticated friends, but accidentally inviting Betty, "the human equivalent of sackcloth and ashes," as her companion. There they encounter Hywel, a dour farmer, Elizabeth, his nervous wife, the aspiring priest Beuno, Hywel's brother and randy Doctor Wyn. Meanwhile Hywel's strange sister Angharad roams the land, observing all, while Lydia is increasingly unnerved by the unexplained laughter that comes down from the hills."--Publisher description.