The cover of 'Killing Trail' by Margaret Mizushima features a serene landscape with a river flowing through a forested area. In the foreground, a woman stands with her back to the viewer, looking out over the river. She is wearing a green jacket and blue jeans. A German Shepherd dog is standing beside her, facing the viewer. The sky is a gradient of orange and blue, suggesting either sunrise or sunset. The title 'Killing Trail' is prominently displayed in large, bold letters at the top, with the subtitle 'A Timber Creek K-9 Mystery' below it.