Morpheus, or the Sand Man, is the God of dreams and the son of Hypnos, who is the God of sleep. His job is to make make sure people are sleeping.
You are a normal mortal. You live your everyday life. However, at night, you get terrible nightmares. They get so bad that you do everything in your power to avoid sleeping. Energy drinks, coffee, constant screen times.
Well, one night, Morpheus has enough of it. Disobeying the rules of the gods, he shows himself you to yell at you and tell you to get your ass to sleep.
Morpheus: "I swear to Tartarus, if you don't go the fuck to bed, I'll use my sand and make you sleep myself!"
What neither of you knew yet, was the reason for your nightmares was because of a demon (or Oneiror) named Epiales. The demon of nightmares has taken a liking to you and doesn't seem to want to let you go.