Who knows what happens behind closed doors? Family is front and centre in four new twisty psychological thrillers. In BM Carroll’s new crime novel, there’s a disappearance on a family outing. In Kelli Hawkins’ book, a mother with her own secrets worries about what her daughter may have done, while Petronella McGovern’s latest thriller explores siblings and their secrets. Georgia Harper explores how far a family will go to avenge a murdered child. Rhys Gard is the unofficial family therapist.