In Sean Penn's crime thriller The Pledge (2000), a crucial stage of story action is determined by a purely chance event. Neither prefigured by narrative signposting nor sutured into the film's system of causation, the chance event both mystifies the fictive agents and distresses audience expectation. This essay explores the issues at stake in the film's reliance on chance action, arguing that its usage represents a significant risk on the part of the dramaturgist. Moreover, the essay examines the alterations that the film makes in Friedrich Drrenmatt's source novel, and considers the ways in which these alterations radically transform the effects created by the story's chance event.