'Person Of Interest' Season 4: Ep 21 Spoilers: Will Jim Caviezel, Sarah Shahi Discover Shaw's "Killer?" [WATCH]

There are only two episodes left for Season 4 of Person of Interest on CBS. In Episode 21, as the battle for supremacy between two Artificial Intelligences heats up, will Finch (Michael Emerson) and Reese (Jim Caviezel) receive help from Control (Camryn Manheim) and discover Shaw (Sarah Shahi)'s whereabouts?

As we previously mentioned, the fourth season started with Team Machine on the run. With new identities, the group had to lay low or else they would be detected by Samaritan's radar. But all things changed during the recent trilogy, which left Shaw taken prisoner by the mysterious Greer. Samaritan even sent in its avatar to deliver a message to the President of the United States.

In our recent recap, the Hustle & Flow actress reprised her role as fan favorite NYPD detective Joss Carter. Carter appeared in flashbacks (hallucinations?) as Reese (Caviezel) attempted to solve one of her unsolved cases. Meanwhile, Root, Finch, and Fusco realized Dominic and Elias are in a violent turf war leaving a trail of dead bodies.

When we last saw Control (Manheim) in part three, Control-Alt-Delete, she discovered Samaritan has actually been using her. At the end of the episode, Control was seen putting the pieces together, realizing there was no terrorist threatening the nation. Samaritan caused the stock market crash and Greer covered up the shootout with Team Machine.

Will Shaw return before the Season 4 finale? In an interview with TV Line, showrunner Jonah Nolan reveals, "Our deal with Sarah is that when she's excited to come back, we're excited to have her."

If Shahi, who is mother of twins, gives Nolan the nod, then "We have a killer storyline for how her character comes back into the universe of our show. We're ready to roll with that just as soon as she is."

Check out this preview from Asylum here:

In an interview with TV Line, POI co-showrunner Greg Plageman, teases Control's role in the two-parter, "One of the most interesting aspects of our show, is to take someone who appears to be a Big Bad, a total villain, and as they start to understand that something else in play, they come over to another perspective."

Person of Interest continues Tuesdays at 10pm on CBS.

Readers, are you excited to see how this season ends?