The synopsis of NBC's crime thriller series "The Blacklist" Season 4 has revealed that though Raymond "Red" Reddington (portrayed by James Spader) and Liz Keen (portrayed by Megan Boone) will be reuniting in the upcoming instalment, the reunion will cost Red dearly.

As reported by Carter Matt, a determined Red will go after Liz and Alexander Kirk aka Constantin Rostov (portrayed by Ulrich Thomsen). The website also states that the Red-Liz reunion might create a lot of problems for the major characters in the series.

The synopsis also states that the Post Office Task Force Samar Navabi (Mozhan Marnò), Donald Ressler (Diego Klattenhoff), Aram Mojtabai (Amir Arison) and Harold Cooper (Harry Lennix) will have to accept their fate and the fact that Liz had betrayed them as she had faked her own death to escape from Red.

After Liz's escape, the Post Office Task Force will be trying her best to find her and Alexander with the help of Raymond. However, it won't be easy to get a hold on Liz this time as things have significantly changed now. Still, Red is not going to take rest before he gets the clue of her whereabouts.

As reported by The Wall Street Journal, Jon Bokenkamp, executive producer and creator of "The Blacklist," said that Season 4 will emphasise on the story of Raymond and Liz as well as the errands of the Post Office Task Force as the chase will continue in the next season too.

It has also been reported that Red and the Task Force will try to convince Alexander to join their side and help them with finding Liz. However, it is not yet revealed whether Alexander will accept their offer or will continue trying his best to save Liz from these two.

"The Blacklist" Season 4 will air on Sept. 22 on NBC.