Alex is on the run and must outsmart Liam and his team to get into her apartment for anything that could help clear her name. Meanwhile, in a flashback to Quantico training, the NATS are tasked with finding a needle in a haystack while looking for potential threats to national security.

The NATs learn surveillance by putting it into practice with Miranda and her troubled son, Charlie. Shelby tries to keep Caleb at a distance, but Raina opens the door to a closer relationship with Simon. In the future, Alex is helped when she tries to hack into an FBI computer.

At Quantico, the NATS attend a class with guest speaker Dr. Susan Langdon. Dr. Langdon is a former agent and profiler who tasks the trainees with looking at serial killer cases to find the one victim that doesn’t fit the case, but when Simon becomes too good at finding things that don’t belong, it’s his life that becomes endangered. In the future, Alex is interrogated by a highly sophisticated FBI team while Ryan’s life hangs in the balance

Alex finds herself in the middle of a congressional hearing to testify about the terrorist bombings. Convinced Elias didn’t act alone, she is determined to find answers and the truth. While back at Quantico, a new group of NATS join Alex and her classmates, causing tension and competition between the groups of trainees.

A terror cell tries to infiltrate Quantico, forcing Miranda and Liam to pay a deadly price. While in the future, Alex continues to get instructions from the terrorist – only this time, it’s Claire Haas’ life that hangs in the balance.

At Quantico, the NATs look into each other’s background to determine who gets high-level security clearance, and in the process Alex, Shelby and Iris learn some surprising truths about Drew, Will and Caleb. Meanwhile, in the future, Alex contacts Claire Haas (guest star Marcia Cross) in order to find her missing friends and is shocked when she discovers what happened to Cale.