In the year 2043, Infinite Dendrogram, the world's first successful full-dive VRMMO was released. In addition to its ability to perfectly simulate the five senses, along with its many other amazing features, the game promised to offer players a world full of infinite possibilities. Nearly two years later, soon-to-be college freshman, Reiji Mukudori, is finally able to buy a copy of the game and start playing. With some help from his experienced older brother, Shuu, and his partner Embryo, Reiji embarks on an adventure into the world of Infinite Dendrogram.