I. Introduction
Recent years have witnessed substantial growth in research on computational models of interactive narrative in digital games [1]–[5]. Computational models of interactive narrative aim to procedurally adapt story experiences in response to players' actions, as well as tailor story elements to individual players' preferences and needs. A common metaphor for interactive narrative models is a director agent (drama manager), which is a centralized software agent that works behind the scenes to procedurally direct a cast of nonplayer characters and storyworld events [4], [6], [7]. The capacity to augment and revise narrative plans at runtime has shown promise for several applications, including entertainment [8]–[10], art [1], training [11], and education [6], [12], [13]. In education, computational models of interactive narrative have been embedded in narrative-centered learning environments for a range of subjects, including language and culture learning [14], social skills development [12], network security [15], and middle school science [16].