Weeks after crash-landing onto a rugged, nearly unpopulated planet Earth, the Hundred have managed to create a sense of order amidst their wild, chaotic surroundings. They work together to feed, shelter, and protect one another from countless dangers, including attacks by violent Earthborns. But their delicate balance comes crashing down with the arrival of new dropships from home--dropships carrying Glass and Luke, as well as the Vice Chancellor and his armed guards.
Suddenly, Bellamy must flee transgressions he thought he had left behind in space, as Wells struggles to maintain his authority on Earth. And while Clark searches for clues about her parent's whereabouts, she finds herself torn between finding them and helping the injured new arrivals in camp. Lives hang in the balance, as the Colonists find themselves fighting not just attackers from the outside, but also enemies from within.