In both academic studies and anecdotal reports, there is widespread consensus that learners tend to learn a language more easily if it is linguistically close to another language in their repertoire, particularly if the languages are genetically related (i.e. belonging to the same linguistic family tree). While there is evidence for such statement to hold true thanks to the phenomenon of transfer, there seems to be an unspoken overarching assumption that the process of learning a genetically related target language is natural and without major problems, and the role of language learner strategies (LLS) is somewhat undermined in such contexts. In light of this issue, this study purports to investigate two areas within the specific skill of reading: (a) learner difficulties that emerge when learning a genetically related language at beginner level and (b) the underlying mental processes that govern corresponding strategy choices. Taking the form of a single case study under a qualitative, constructivist paradigm, this research depicts the self-studying journey of a male Taiwanese individual, who, as a former Russian language learner, learns to read a closely related language—Ukrainian. With data from reading task sheets, stimulated recalls, and a semi-structured interview, the findings identify four learner difficulties that surface when starting to read in said context, thus problematising the aforementioned general claim that a genetically related target language is largely straightforward to learn. The data also shed light on thinking processes fundamental to the decision of strategies, advocating a critical convergence between the fields of language learner strategies and second language acquisition in the discussion section. Finally, the contributions, pedagogical implications, and limitations of the study are addressed in detail.