ABSTRACT Emotion-focused therapy for couples (EFT-C) is therapy which has a substantial evidence base both for process and outcome studies. However, to date there have been no in-depth empirical case studies that track interactional and emotional transformation in the couple, minute-to-minute, across the entire course of therapy. This case study aimed to observe the interactional transformation and emotional transformation in a couple over 11 sessions of EFT-C therapy. Videos of each session were analyzed using theoretically informed qualitative psychotherapy research. Results showed clients presenting with a negative interactional pattern, which appeared to be composed of two separate but linked cycles. Over the course of treatment, the clients presented with secondary emotions and behaviors including criticism and withdrawal. The individuals within the couple progressed at different rates through the expression of core pain and unmet needs, and after several sessions they were able to give and receive compassion to each other. They also showed signs of beginning to self-soothe more effectively and let go of some pain. The expression of assertive or healthy anger was found to be particularly important for the change in their interaction. Strengths, limitations and ideas for future research are discussed.