Meet 11-year-old Pea and her definitely not ordinary life…. When Pea's single mum becomes Marina Cove, best-selling author of the Mermaid Girls books, everything changes. It's time to leave their tiny flat in Tenby for a proper house in London, and a whole new life. Pea likes the red front door, and the having attic bedroom all to herself. But there's an empty chair beside her in every lesson, and no one seems to want to fill it….