Martha's decided friends are stupid. Especially if they're anything like Colette and Chloe. She never wants another friend. Ever. But it's the first day of the summer holidays, and there's not that much to do...until she spots a strange little furry creature who leads her to Opal Moonbaby. Opal's been sent down from her planet on a mission: to work out what on earth people are (and my goodness - people are strange) and to make a friend.