Yesper always says YES and Noper the opposite, but the Thief who has escaped from jail does not care about either YES or NO. When Yesper and Noper pursue the thief, they are tricked, and Yesper must go to prison. Fortunately, everything turns out well, and Yesper learns that sometimes you do have to say NO.

The Thief Strikes Back received both the Brage Prize and the Critic’s Prize .

The rights have been sold to China, Czech Republic, Egypt, Germany, India (Hindi, Bengali and English) , Italy and South Korea.