The insect rosary - Sarah Armstrong

'I have a gift for you and Nancy.' She put her hand into her pocket and pulled out two little plastic bags. There were two strings of rosary beads, black and shiny like a line of beetles.
All families have secrets, but Bernadette's are more dangerous than most. On holiday in Northern Ireland in 1982, she and her older sister discover their family is involved with disappearances and murder. Thirty years later Nancy makes a disastrous return to the farm with her own family. The events of the past gradually and menacingly reveal why those sisters have not spoken to each other since that last disturbing summer together.