A young girl from Taiwan, China goes to the deserts of Gansu province not to lament, but to plant. She joins forces with a dedicated planter, Mr Ma, who has been holding back the sand for 19 years. Together, they help to build the "Green Great Wall" of saxaul trees, one shovel at a time. But the journey doesn't stop there. She follows the water to its source in the Qilian Mountains, meeting the next generation of guardians protecting the water that sutures life downstream.