The Worst Thing About My Sister : Paperback : Random House Children\'s Publishers UK : 9780440869283 : 0440869285 : 06 Dec 2012 : Marty and her sister Melissa couldn\'t be more different. The sisters can manage to live together, despite their occasional scraps but then Mum tells them they have to share a room. The girls soon discover that being too close can have unexpected consequences, and when an accident happens, the sisters realise they are closer than they thought.