A diverse group of recruits has arrived at the FBI Quantico Base for training. They are the best, the brightest and the most vetted, so it seems impossible that one of them is suspected of masterminding the biggest attack on New York City since 9/11. As we intercut between their hidden pasts and their present training, we also flash-forward to the near future, where one of the recruits will turn out to be a sleeper terrorist.