After dying during what is supposed to be a life-saving surgical procedure, the protagonist wakes up in a strange place where they’re asked to choose a future for themselves. Continue to an unknown afterlife, or take a chance on a new lease on life as something called a Dungeon Core. Choosing the latter, the protagonist finds themselves split in two. Cyan, a boy fascinated by science and fantasy, and Magenta, a girl with a love of history and architecture. Together, along with their strange Guide and a few other allies, they must adapt to this new life and find a way to thrive.