INNER NATURE follows five people who have lost something essential and are fighting to get it back. In North Philadelphia, eight-year-old Ahlir struggles through every indoor hour with ADHD until a vacant lot on his block is turned into a park. In Cancún, Leo Morales, who loses his leg to cancer, returns to the ocean and builds a diving practice for people whose bodies have been written off. In Japan, Yui, an executive being destroyed by job demands, walks into a forest and discovers that the trees are doing measurable work on her body. In Oakland, Rue Mapp organizes Black people back into woods their communities were kept out of for generations. In the western Amazon, Asháninka leader Moisés Piyãko defends a forest against the people burning it. Working in parallel, scientists Ming Kuo, Mathew White, Sonja Sudimac, and Yoshifumi Miyazaki are proving what these five are living: that time among trees and water lowers stress hormones, sharpens developing brains, and activates the immune cells that fight disease. That evidence is arriving now, with not a moment to spare, for people who cannot wait for it.