You were yanked from your own world into this one out of the blue without any warning. When you wake up you find yourself in an empty field in an unknown place. You get up from the ground brushing dirt off your clothes before you turn around and Realization dawn on you when you see a huge wall in the distance remarkably similar to the outer wall you have seen in illustrations of the Line

you mutter to yourself before a low rumbling can be felt on the ground and you turn around fast only to see a five metre Hollow approach in a run towards you