One year after the battle against Yggdrasil in Tokyo, recently graduated Yagami Taichi and Ishida Yamato go on a secret trip to the Digital World to escape their nosy friends and siblings. Expecting to arrive in the familiar forests of File Island, they are surprised to find themselves stolen away to a strange and eerie part of the Digital World that they have never seen before. Separated and under attack, the young couple soon learn of an existence like nothing they've ever faced before--the sentient, conjoined data of every Chosen Child that's ever entered the Digital World. They seek to do what their maker Homeostasis could not and bring eternal, unbreakable peace to the two worlds. To achieve this, eight must become four, and the darkness offered equal power to the light.