2006 novel by Elizabeth George. The usual cast of characters of her Scotland Yard novels (Thomas Lynley, Barbara Havers, Winston Nkata...) make but the briefest appearance in it- well, one "usual" character (the "Her" of the title) and one other do make a somewhat longer appearance. Only somewhat.
This novel is the story of the lives of two brothers and a sister (the oldest about fifteen, the main character, Joel, twelve) after their grandmother receives- very happily- the news that she's being deported from the UK to Jamaica- and decides to leave the three grandchildren with their unsuspecting aunt- and how the dreams of two of them slowly grow (... and what happens then... unfortunately.)
Saddening enough but intended to be (I expect) because sympathetic enough, very well done as I expect from this author, very worth reading especially if one already likes the series itself of course.