December 20th, 198X. Mysteriously, people across the globe witness the same dark dream. Soon after, the number of humans unable to wake from their sleep begins to increase steadily. There are reports of life-like "R-dreams" that are experienced collectively and haunted with "Zel" - nightmare creatures. Hokuto, a struggling art student, is doubtful of R-dreams until he falls into one. There, he meets new friends, battles with the Zel, and tries to understand the nature of this dangerous phenomenon.