Story
At first, there was only Winter. But this lonely existence was too much for it to bear, so Winter split off part of itself to bring forth Spring. But the earth wished for Summer and Autumn as well, and their creation marked the birth of the four seasons. The changing of seasons became a duty that fell upon humanity, and those tasked with the transition are known as "Agents of the Four Seasons." This is the bittersweet story of Hinagiku and Sakura - the Agent of Spring and her devoted Guard, who set out on a journey to usher in Yamato's first spring in ten long years.
Synopsis via AniList (English).
