In The Inside, a pregnant woman named Sarah moves into a new home with her husband. However, when her water breaks early, she finds herself trapped in her house by a group of violent vagrants who have taken over the neighborhood. As she struggles to survive the night, Sarah begins to experience strange and terrifying visions of a supernatural entity that seems to be connected to the vagrants.
As the night wears on, more and more of Sarah's friends arrive at the house, seeking refuge from the rampaging vagrants. But even as they band together to defend themselves, the entity's presence grows stronger and more malevolent, and it becomes clear that they are not dealing with a human threat.
What follows is a nightmarish descent into madness and horror, as Sarah and her friends battle both the vagrants and the supernatural entity that is preying on them. Will they be able to survive the night, or will they succumb to the terrifying forces that have taken hold of their home?