The terrorist was revealed on “Quantico,” but Alex still has to take him down. In the previous episode, Drew was shown to be one of the bombers. He tricked Alex into planting evidence on Ryan’s computer to frame him as the terrorist and then Alex had to steal Ryan’s car, which had the nuclear bomb in it. In episode 21 of the ABC series, she’ll still be on the run.

“Alex learns someone she cared about at Quantico is not who they seemed to be, as she finds herself at the heart of another possible attack,” the synopsis teases. It appears that special someone may be an agent other than Drew (Lenny Platt). The trailer for episode 21 asks, “Who is the traitor?” It looks like “Quantico” Season 1 hasn’t revealed all of the secrets just yet. Watch the promotional video below:

The video also reveals that others will find out that the next attack doesn’t involve a typical bomb. Miranda (Aunjanue Ellis) knows that a nuclear weapon is involved, but the FBI will have to work quickly. It looks like Alex (Priyanka Chopra) is driving the nuke into the heart of New York.

Showrunner Joshua Safran dropped a couple of hints about the penultimate episode of the season. He told Entertainment Weekly that what Alex uploaded to Ryan’s (Jake McLaughlin) computer will be quickly disclosed. Also, Simon’s (Tate Ellington) fate will be revealed in this episode, titled “Closure.” The last time viewers saw him, he was being shoved into a van and taken by the terrorists. “You will find out in the very next episode ... I’m not going to say [if he’s OK], but you will definitely know the answer,” Safran said.

As usual, “Quantico” Season 1 will also show the present day. “The NATS are excited that graduation is near as they prepare to leave Quantico and head out into the real world for their new assignments,” the synopsis says. The group was separated at the beginning of the season, so it looks like fans will finally see how that happened.

“Quantico” Season 1, episode 21 airs on ABC Sunday, May 8, at 10 p.m. EDT.

Quantico Alex Alex (Priyanka Chopra) is forced to drive a nuclear weapon around in “Quantico” Season 1, episode 21. Photo: ABC Quantico women Iris (Li Jun Li, left), Alex (Priyanka Chopra, center) and Shelby (Johanna Braddy) work on a case in “Quantico” Season 1, episode 21. Photo: ABC Quantico Claire Claire (Marcia Cross) returns in “Quantico” Season 1, episode 21. Photo: ABC Quantico Caleb Caleb (Graham Rogers) works on one of his final training exercises in “Quantico” Season 1, episode 21. Photo: ABC