I'm not entirely sure of all the specific details, but generally it might involve the girl being trapped in a small space within a wall. There could be a struggle for survival and a long period of isolation.
It's hard to say for sure. Sometimes stories like 'The Wall' draw inspiration from real events but might have fictional elements added for dramatic effect.
Well, 'The Wall 2017' is not based on a true story. It's likely a product of the imagination of the writers and creators, designed to entertain rather than depict real events.