In series 3, Emily and Katie are introduced as twins. It seems that Emily is always in Katie's shadow. They are in the same year a college, and Emily tries to break free from Katie's shadow. Katie starts suspect that Emily has feelings for Naomi, much to her disapproval. The twins fight a lot. After Katie is hit over the head with a rock by Effy, Emily is shown to support her sister, and goes to college to complete Katie's history exam in disguise. The twins attend the Love Ball together, along with JJ and Freddie. Katie is upset when she finds out that Emily slept with JJ and did not tell her. At the Love Ball, the twins fight over Katie abusing Naomi, but Emily stops fighting and helps Katie up. She tells Katie that she is in love with Naomi, and that she also loves Katie, and that she'll never really leave her.
In series 4, Katie and Emily have less of a strained relationship, due to Katie being more accepting of the fact that Emily is gay; however, they still argue a great deal over their mother's inability to come to terms with it. Emily moves out of the Fitch home due to her mother's unacceptance, despite Katie's plea for her to stay. In Katie's centric episode, she finds out that she has premature menopause, and won't be able to have kids. She calls to tell Emily, but there is no answer. When the Fitch family is evicted from their home, Katie suggests they move in with Naomi and Emily. While Katie surprisingly defends Naomi to Jenna at first, she is startled to learn about Naomi's affair with Sophia; when Jenna tries to use this as justification for her homophobia towards Naomi, Emily yells at her and chases her out of the house in tears. Emily and Katie get in a fight, resulting in Katie slapping Emily in the face. Later, Katie finds Emily crying over Naomi, and the twins comfort each other. In the final episode, the twins have a better relationship. When Naomi comes to apologize for cheating and forgive Emily for attempting to do the same, Emily looks for her sister's approval. Katie nods her head and Emily continues to kiss Naomi. The twins are shown to be happy at the end of the series.