Vicious nightmares are much different from the regular ones: they are vivid almost like reality, persistent and recurring over an extended period of time, and most dangerously, they create physical injuries and extreme side effects called "malady." Shamans—individuals blessed with spiritual powers—perform rituals in which they enter the affected person's dreams and eliminate the "nightmare seedling" that is causing the vicious nightmares.

When 24-year-old Han Jungoh lands a job as a shaman's assistant, he ends up in the client's dream despite having no spiritual energy. His boss, the serious yet oddly adorable Shin Ibeom, is not too thrilled about Jungoh's interference with his work. However, Ibeom suddenly develops a malady—his body becomes hot and his head dizzy, unable to resist his physical desires. Too distraught and embarrassed to turn to his family, Ibeom asks Jungoh for help, swearing that his attraction is nothing but a bothersome side effect.