In a world exhausted by war, protagonist Lian receives an unusual gift: a science book titled "7 Days in Dream," which describes a substance called Guangchen capable of granting any wish. A scientist named George tells her it is about to appear and that they must find it quickly before anyone else does — and make a wish that ends the fighting. Over the seven days they spend searching, Lian recovers memories she had lost, and discovers that the chain of events surrounding Guangchen is not what either of them believed.