After an accident leaves her sightless, crisis hotline counsellor Samantha Creed devotes herself to helping troubled callers back from the brink of despair. But when Sam decides to step down, one of her frequent callers does not take the news well. On her last night on the job, Sam faces a terrifying visit from John a frequent caller who feels betrayed by her leaving. But John is no ordinary caller. He's a sadistic serial murderer she's unwittingly kept from killing himself for over a year. With only a skeleton crew on the graveyard shift, there's very little that stands between John and Sam. He's come for her and won't let anything or anyone stand in his way. Can Sam survive the longest, darkest night of her life?