After 27 years apart, American middle school teacher Ronald Sakolsky traveled to the Mu Us Desert in Inner Mongolia Autonomous Region to reunite with desertification fighter Yin Yuzhen. They didn't share a language, yet they understood each other. Today, 80% of this land has turned green, and a new generation of young people around the world carries on the work. A promise planted long ago has grown into a living legacy. A CGTN production, One Earth, One Promise, is coming soon.