Every night, Hong Yushin is tormented by vivid dreams in which he is assaulted by a mysterious monster. As the effects of the recurring nightmares begin to bleed into his waking life, leaving him overwhelmed with frustration and unable to function, a man named Yeom Ju-eon appears—claiming to be an exorcist. Now living under the same roof, the two begin a series of rituals to banish the creature haunting Yushin’s dreams... but the line between nightmare and reality only grows thinner.