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Neutrophils—a type of white blood cell—not only respond to microbial infections, but also to sterile injury caused, for example, by trauma or organ necrosis. McDonald et al. used dynamic in vivo imaging to observe how neutrophils (green) are rapidly recruited to the site of dead liver cells (red) via intravascular channels (blue). A multistep hierarchy of directional cues guides the neutrophils through the vasculature to the site of injury, thereby limiting collateral damage to the surrounding healthy tissue.