Quantico is an American television series created by Joshua Safran and produced by ABC Studios. Priyanka Chopra stars as Alex Parrish, a bright FBI recruit, who after graduating from the FBI Academy, joins the agency and later becomes a prime suspect of a terrorist attack on Grand Central Terminal.

The main cast include Priyanka Chopra, Jake McLaughlin, Yasmine Al Massri, Johanna Braddy, Tate Ellington, Graham Rogers, Anabelle Acosta as her fellow recruits, and Josh Hopkins and Aunjanue Ellis as their trainers at the FBI academy, Quantico, Virginia. In the second season, Russell Tovey, Pearl Thusi, and Blair Underwood were added to the main cast following the CIA plot elements. In the third season, Marlee Matlin and Alan Powell were added to the main cast.

Alexandra "Alex" Parrish (portrayed by Priyanka Chopra), a former top recruit at Quantico as well as a promising FBI agent was considered a prime suspect in the Grand Central Terminal bombing. She was later pardoned after the real mastermind terrorist behind the Grand Central bombing and the Command Center bombing in New York was revealed.

After the negative publicity to the FBI stemming from Liam O'Connor's treachery as well as Simon Asher's death at Quantico, Alex is fired by the organization. Two months after the presidential election ended, Alex is approached by CIA director Matthew Keyes, who provides an opportunity for her to join and work for the organization. After working as a CIA analyst for six months, she is given an undercover assignment by the FBI. She is tasked to pose as a CIA recruit at The Farm in order to expose the rogue faction within the agency called the AIC.

Months after leaving The Farm, a hostage crisis at the G-20 summit in New York is declared by a terrorist group called the Citizens Liberation Front. Two weeks after the end of the crisis, former President Claire Haas and CIA director Matthew Keyes put forth a covert joint task force, between the CIA and FBI. Alex was reinstated to work as an FBI agent. Shortly after the task force is formed, Clay Haas was assigned as the leader of the group. Alex and the team were tasked to expose a syndicate of eight collaborators that were secretly involved in orchestrating the hostage crisis. After a national scandal involving the resignation of President Claire Haas along with the disbandment of the task force, Alex resorted to a final strategy. She released U.S classified intelligence to the public at the Constitutional Convention in Philadelphia, implicating newly inaugurated President Henry Roarke in a deadly conspiracy. As a result of her actions at the Convention, she is branded as a fugitive of the United States. After being issued a Red Notice for her arrest by Interpol, she leaves the country with Ryan Booth on a plane to Thailand in order to evade the authorities.

Liam O'Connor (portrayed by Josh Hopkins; season 1), a seasoned FBI agent who had a fling with Miranda Shaw in the past. Years ago, he and Alex's father had graduated from the FBI academy together and one of their first undercover operations in Omaha was a blown sting killing over 200 people. Years later, he worked a sting operation against some militia groups in Chicago. Just before the case went south, ending in a shootout with three confirmed casualties including Drew's fiancée and unborn child, he had told Ryan that he would take the blame and that Ryan would be his replacement. However, it was later revealed that Ryan took the blame for the incident, later losing his position within the Bureau.

One year prior to the Grand Central bombing, it was revealed that Liam was demoted from his position within the Bureau. However, Miranda pulled strings to allow him to work as an instructor at the Academy. During his time at the Academy, he had a one-night stand with one of the recruits, Alex, on New Year's Eve. Although Miranda discovered the incident, she was shortly dismissed prior to pursuing the misconduct case with Liam. Sometime later Liam was promoted to the position of Assistant Director, replacing Miranda's former role at the Academy.

Months after Alex and the recruits graduated from Quantico, Liam was assigned to work in a field office based in Washington. After the Grand Central bombing occurred, Alex was considered a main suspect in the case. As a result, he pursued her until she managed to clear her name. Three months after the Command Center bombing occurred, it was revealed that he testified against Elias Harper in the congressional hearing case. Later Miranda discovered that he was the true terrorist behind the two bombings in New York, right before he shot her. It was subsequently revealed that he had used hidden cameras and tracking devices to plan the bombings, and had gathered intelligence to blackmail Elias and frame both Alex and Simon. His objective was to destroy the Bureau before the organization got an opportunity to destroy the country. Initially, he tried to frame Miranda, but Alex and the others discovered his plan to plant a bomb at the FBI Academy, the day the new recruits were graduating. He was unsuccessful; the bomb was later defused by Simon's actions. Subsequently, he was killed by Alex and Ryan.