During a summer in a mountain village, sixth‑grade student Nozomi Nanase stays with her grandfather, a family doctor who runs a rural clinic. Surrounded by abundant wildlife, animals and insects that thrive freely, Nozomi learns that lizards possess unique cells capable of regenerating body parts. Guided by her grandfather through the natural world and the marvels of human physiology, she discovers the science of induced pluripotent stem (iPS) cells and their vast potential for the future.