My case study of 'Heart of Darkness' analyzes the role of image schemas in shaping narrative macrostructures and in organizing literary metaphor systems. Assuming that we can reconstruct global story meaning from local image-schematic metaphors, I propose a model in which compound gestalts represent major aspects of the plot-defining macrostructure. It emerges as salient textual cues progressively add up to a scaffold of image-schematic elements that represent the event's overall texture, its "plot-gene". The rich metaphor system of 'Heart of Darkness' throws into relief the amazing range of literary functions rooted in this image-schematic plot-gene, including plot mnemonics, inference, metaphor networks, and clustering of propositional knowledge, megametaphor, focalizing and viewpoint effects, irony, as well as mood contours. Progressing toward a cognitive model of narrative, I will argue that reading involves a mental simulation of how image schemas interact topologically to produce emergent effects. I dub the imagistic substrate of this simulation the "mental (story) sketchpad," following Baddeley (1986). (Michael Kimmel)