A young man experiences a vivid dream where he engages in an intimate encounter with a stunning cosplayer named 'Purimu', who addresses him as her master. Upon waking, he is startled to realize the dream was more than just a fantasy. Fearing the worst, he initially flees from her, convinced she is a dangerous prostitute seeking to harm him. However, their paths cross again, leading to a surprising liaison on a rooftop where he uncovers her true identity as a succubus, a seductive creature of desire and temptation.