Lucy Semple has just one wish: that everything might always go on exactly the same, without upsets of any sort. Yet even before she returns to St Ruth's School, she knows it is going to be an awful term, for a heretofore unknown cousin arrives from some remote island. Not only is Sabina clueless of the ways of proper English girls, she speaks with a strange accent, her hair is cut like a boy's, and she has the most embarrassing habit of saying whatever comes into her head. To add insult to injury, a favourite mistress has been replaced with an outsider, money goes missing and suspicion abounds, and a fire breaks out in one of the bedrooms. Lucy is not alone in thinking this is a most awful term. Will light finally shine in the darkness?