Yumekui Merry, also known as Dream Eater Merry, is a Japanese anime series that follows Yumeji Fujiwara, a high school student who has the ability to predict dreams. His life changes when he meets Merry Nightmare, a girl who has wandered into the real world from the world of dreams. Together, they battle dream demons that possess human hosts, aiming to prevent nightmares from taking over reality.