Born with a serious heart condition, Dara has been waiting for his Big Operation forever, and this summer it’s finally going to happen. The moment his heart is fixed he’ll row out to the island in the bay all by himself just like he’s always dreamed. But when his op is postponed, Dara snaps. When will he get to live his real life? Maybe the adventures he dreams of are simply impossible. And then he finds a girl hiding in the boat shed. She wears animal skins. She has a real live pet wolf. She is, simply, impossible. Could Mothgirl really be from the Stone Age? And what is she seeking on Lathrin Island? As Dara and Mothgirl set out on a wild, windswept sea journey Dara begins to realise that when you stop worrying about what’s impossible, you can do anything.