In the skeletal muscle, energy distribution has been proposed to occur through metabolite-facilitated diffusion, although genetic evidence has raised questions about the importance of this mode of distribution. Using various forms of high-resolution microscopy, Robert Balaban and colleagues explore whether the mitochondria themselves — as well as actually generating the energy — also have a role in its distribution. This cover represents an artistic 3D surface rendering of FIB-SEM volume segmented data.