"It's done " said Nell. "My invention is finished I must show it to the people in the Big City as soon as I can." Far from Nell's home in the countryside, the Big City is growing more polluted every day--and Nell has a brilliant mind and an ingenious invention. She sets off on the long journey, only to find that the problem is far worse than she'd imagined. But Nell is determined to succeed. A beautifully illustrated picture book about...