Dream, what exactly is it? It is a wonderful state in which we slightly squint our eyes under the afterglow of the setting sun, wandering on the edge of sleep and awakening. Most people in this world have experienced the charm of dreams, but there are only a few people who can truly remember the details of their dreams and tell them about them. However, in this complicated world, there is a group of special people who shuttle between dreams and reality, like guardian angels. At the critical moment when people fall into nightmares, they save the souls who are about to fall into the dark abyss and lead them back to the bright real world. These people are called "dream cultivators".