Long ago, a mysterious shrine maiden sealed nature spirits within forest trees to stop them from terrorizing the world. Now, her descendant, a cheerful young princess named Suzu, is prohibited from going outside. However, one day, after sneaking out into an area known as the 'forbidden zone,' Suzu discovers a strange seed which grows into a fun-loving nature spirit. With her new friend, Suzu is eager to explore the outside world that she has been kept from, despite not knowing the dangers of the forbidden zone—or why the seed was being kept there.