Carrie Mathison (Claire Danes) and Peter Quinn (Rupert Friend) will once again work together to solve a big mystery in the penultimate episode of "Homeland" season 6.

In the trailer for the upcoming episode called "R Is for Romeo," Quinn is heard telling Carrie that he has proof about the identity of the person responsible for the explosion of the Medina Medley van.

Another scene also shows the two trying to figure out some clues that are wiped from a used whiteboard. Quinn figures out that the letters could indicate the time and location where the men hired by Dar Adal (F. Murray Abraham) are heading. Carrie, on the other hand, sees a big letter R on the board. This could help them in their investigation.

The trailer also reveals that Saul Berenson (Mandy Patinkin) will present a new evidence to President Elizabeth Keane (Elizabeth Marvel). However, it is not clear how the president will act after Saul's revelation.

According to the synopsis of the episode, the president will make a very important decision. But will the public accept the president's act after getting all the criticisms in the previous episode?

In the final moments in the trailer, fans of the series can see that Carrie will be in danger once again when a man comes out of nowhere to abduct her.

On the other hand, the synopsis also reveals that Max (Maury Sterling) will get himself in trouble in the upcoming episode. This can be seen in the trailer, when Dar himself confronts the freelance surveillance expert and tells him that he has no idea about the kind of trouble that he has put himself into. Can he still get out of the black ops specialist's clutches?

Showtime will air the penultimate episode of "Homeland" season 6 on Sunday, April 2, at 9 p.m. EDT.