In "My Sister Stole My Identity," the narrator shares the unsettling experience of their sister adopting their name, style, and even interests, leading to confusion and frustration. Initially, the narrator feels overshadowed and invisible as their sister garners attention by mimicking them. The situation escalates, causing rifts in relationships and a struggle for the narrator to reclaim their individuality. As the story unfolds, it becomes a journey of self-assertion and the quest to establish their unique identity amidst the chaos of sibling rivalry.