After a war with the grounders, Ari wakes up in a unfamiliar white room. She is unaware of her location or the fact that for almost 100 years people have been surviving in a underground bunker known as Mount Weather. The 47 take shelter in the Mountain and start to settle in, even Ari makes friends with a boy who carries an unknown seceret. Of course that was just the calm before the storm. After all, nothing is ever as it seems on the ground.