Elvira Carr is twenty-seven, neuro-atypical, and has never lived alone. But her father – who she suspects was in the secret service – is dead, and when her mother has a stroke and is taken into care, Elvira suddenly finds herself home alone. In order to cope, Elvira – who knows a lot about biscuits and supermarkets, but not much about life – develops Seven Rules for interacting with others. Not even her rules can help her, however, when she’s faced with solving a mystery she didn’t know existed.