Sometimes, it takes only one person to start a movement. This captivating documentary tracks teenage climate activist Greta Thunberg for a momentous 13 months, from her initial school strike for climate justice outside the Swedish Parliament to her astonishing wind-powered voyage across the Atlantic Ocean to speak at the UN Climate Action Summit in New York. With remarkable access to Thunberg and her father, Swedish director Nathan Grossman paints both an intimate and candid portrait of a savvy, indefatigable girl unafraid of her detractors and an inspiring look at her unceasing battle to save the planet.