Nicoismysenpai
If you dial the number 4444, no one will pick up. But fall asleep afterwards, and a man will visit you in your dreams. He will introduce himself as an assassin of sorts, and you will tell him your darkest desire. After all, the Dreamwalker can become your enemy's worst nightmare...for a price.
Nathan Lee is many things: a slacker, a skeptic, and above all, hopelessly infatuated with the illustrious Aurora Kim. But when he accidentally swaps phones with a stranger, he ends up face-to-face with Cyr, a contract killer who travels through dreams. And his next target is Aurora.
Desperate to save Aurora, Nathan takes it upon himself to hunt down Cyr's client. But when the bodies begin piling up, Nathan is forced to question who Aurora Kim really is...and what it will cost to keep her alive.
(Prompt #56: After grabbing the wrong phone at a busy deli, you discover the stranger's life is far more tangled with yours than you ever expected.)