Yumeji Fujiwara, a young male student like any other, gained the power to see the aura of other people's dreams, and is able to predict what kind of dream they will have next, after an event that occurred 10 years ago. Since then, he started to have weird dreams with cats following him for an unknown reason, where he learns thanks to the boss of the cat army, John Doe, that his body is needed to access the real world. One day, as he was about to come back home after his errands, a mysterious girl falls on top of him. This girl, called Merry Nightmare, is actually a dream demon (夢魔 muma?), who's searching for a way to come back in her world.