After she and her friends are attacked by a dark cloud, Zanna spends the next two nights at Deeba's house.
With the help of Fing, Skool (a friend of Fing's in an old-fashioned diving suit), Conductor Jones, Rosa the bus driver, and the Slaterunners (a tribe of people who walk only on roofs), Zanna and Deeba make their way to the Propheseers where they learn more about the Smog.