The authors investigated narrative competence, sociocognitive abilities and emotion comprehension in a 9-year-old child (FS) with Cri-du-Chat Syndrome (CdCS) who had only a mild mental delay and relatively preserved language. Considering that the production of narratives is a major step in development and in the acquisition of learning skills related to conceptual, linguistic, structural, and pragmatic knowledge, and in the development of psychological lexicon, that is, the ability to use theory of mind (ToM) processes also in atypical development, this case provided an opportunity to study aspects of this genetic syndrome never investigated before. The authors found that the child's performance on different stories was comparable to that of chronological age controls for several narrative and emotional competences and even better than that of mental age controls. However, her ability to reason was still incomplete according ToM; in fact, FS was able to express her mental states, but she was unable to understand emotions, specifically mixed emotions. This finding suggests that in CdCS children with a well-developed language narrative and emotional competence could be a point of strength for improving their social skills with important effects on their familiar and school life. Also in CdCS children with the typical poor developed language, the narrative discourse could be introduced in their communication by means of any type of alternative language (i.e., sign language or augmentative and alternative communication) to improve their social abilities and to reduce behavioral disorders due to the difficulty in expressing their personal experiences.