This paper explores the role of narrative in decoding diagrams. I focus on two fundamental facets of narrative: (1) the recounting of causally related sequences of events, and (2) the positioning of the narrator through point-of-view and voice. In the first two sections of the paper I discuss philosophical and semiotic frameworks for making sense of mathematical diagrams. In the third section I draw on theories of narration, exploring the way that narrators position themselves both inside and outside the story world. In the last section I use the narrative concept of 'virtual voicing' to analyze data collected from a research experiment.