Marty & her sister Melissa couldn't be more different. Marty loves her Converse trainers playing football hiding in her secret den & helping her dad with his DIY. But Melissa loves Justin Bieber & all things pink girly & pretty. The sisters can manage to live together despite their occasional scraps but then Mum tells them they have to share a room. For Marty having to share her bunk beds & lose her private sanctuary turns out to be the very worst thing about having a sister. But the girls soon discover that being too close for comfort can have unexpected consequences & when an accident happens the sisters realise they are closer than they thought.