When I'm a famous marine scientist I'll live on a boat by myself. I'll snorkel on the reef all day long. But before I can learn to snorkel I have to be able to swim properly. And right now, I don't even own a swimsuit.Eleven year old Tilly dreams of becoming a marine scientist. But she lives in a drought stricken town with her mum and younger brother Oliver, who is autistic. Oliver's meltdowns are making life unbearable. He can't cope with even the smallest of changes to his routine.On top of that, he needs so many different kinds therapy that there's never any time or money left over for swimming lessons. When Mum loses her job and decides to move the family to the Queensland coast, Tilly is excited and terrified all at once. Is this her chance to finally learn to swim? Will her dream of snorkelling on the Great Barrier Reef come true? Or will so many changes all at once prove too much for the whole family?