This paper reports results from a study which examined viewers' cognitive and affective responses to an interactive TV drama. Ten participants were videoed interacting with 'Our World War' [1], and then interviewed about their experience using the video playback as a retrospective prompt. An interpretative framework was designed to guide analysis by probing themes of narrative engagement identified in previous literature. We report findings relating to five themes of engagement: cognitive, affective, perspective taking, competence and autonomy, and transportation. Our data adds to the existing literature on interactive stories by highlighting the pivotal role of the self in engaging with interactive drama, with self-reflection emerging within each theme. We conclude that two experiential states drive engagement: a transported experience; and one in which self-reflection limits transportation.