The book focuses on nouns declension in Czech language. It is a gripping story with sci-fi elements, the main characters are the aliens Fi and Flo.
In each chapter, there is always one pattern word highlighted in all its singular and plural forms. Readers learn how to identify the word with the pattern and to understand the orthographic differences between the similar forms.
Each chapter is followed by a table of the pattern word paradigm with a commentary and a warning about the problems that are related.