The present article offers some of the results of a comparative analysis of the English and Spanish translations of a juvenile novel originally written in German: Greg, Eine ratselhafte Verwandlung. Drawing on polysystem theory, the article investigates how the two target texts shape the construction of an identical world. The aim is to demonstrate the importance of preliminary norms for the translator of literary texts written for children or young people: the different social and educational conventions followed in those target languages (English and Spanish), and the different focus on the young reader on the part of the translators. This is achieved through the study and analysis of the different strategies put into practice by the translators, notably the use of cultural markers such as anthroponyms and hypocorisms, diastratic and diaphasic varieties, and juvenile expressions in language.