Deeba and Zanna are friends. Deeba discovers strange things around Zanna. Many people keep calling Zanna Schwazzy. However, she doesn’t know the meaning of this peculiar name. One day at the schoolyard, Zanna is surprised by noticing a fox staring at her before it dashes away. Zanna becomes worried and accompanies Deeba to spend a night at her place. The two friends are further shocked after seeing a broken umbrella crawling like a spider to spy on Zanna. Deeba and Zanna decide to trail the umbrella to a particular basement. However, they find themselves in a strange world called Un Lun Dun.
Un Lun Dun is a strange world where everything is a mystery to them. Every person who comes across the girls humbles himself or herself before Zanna. In this peculiar world, Zanna is perceived as Schwazzy or the special one. People believe that Zanna is picked to get rid of the Smog in Un Lun Dun. Deeba and Zanna meet strange people who want to befriend them. Moreover, agents of Smog are also looking for Zanna. Lastly, the two girls are led to the Propheseers by Fing. Upon arrival, they are attacked by fellows who have been addicted to the fumes of smog.
Zanna inhales Smog's fumes and becomes unconscious. Deeba takes her to London, where she becomes conscious but forgets about being in Un Lun Dun. The author is trying to warn people of London against the environmental impacts of materials dumped in the city like umbrellas and bins. All the filthy and garbage dumped in the city may have environmental repercussions. People should strive to preserve the environment.
