The season one of "The Blacklist" opened with Red surrendering to the FBI and cutting a deal with them. In exchange for his immunity, he would tell FBI the names of the most dreaded criminals, including the ones who are not even on their radar. At the time, Red made it clear that he would only communicate with Elizabeth Keen, and no one else. The Episode 21 of "The Blacklist," "Berlin," answers the question why Red surrendered to the FBI in the pilot episode. It was a very well thought, calculated move. Red was not helping FBI, but the FBI was helping him to decimate some of the allies of his mysterious enemy called Berlin.

The episode does not reveal why Red picked Liz, but it does show what happens when Liz decides to stop communicating with Red. The big bosses of the FBI throw Red's immunity deal out of the window and order his arrest. Also, Red surrends, again, but this time he kneels down in front of Liz.

Here is the Recap of "The Blacklist" Episode 21 'Berlin':

The episode opens with a man coughing up blood at home and soon the blood is coming out of his ears. While on his way to a bank for a pick-up, he checks a syringe, which is full of some liquid, but does not inject himself with that. At the bank's bathroom, he calls up 911 and asks for a particular doctor. However, he does not tell why he is calling and asking for a doctor. He records a goodbye message for his family, and dies. The people present at the bank are quarantined, as the dead man might have died of a highly contagious disease.

At Liz's apartment, Agent Ressler is checking the mess in her living room. Liz has told him all about Tom. She wants to take Tom apart piece by piece until he answers all her questions. Agent Ressler promises to help her in that. But, he is not sure how Cooper and the bureau will react to the revelation about Tom. Liz tells whatever she knows about Tom to the FBI. She tells them that she wanted to investigate how deep Tom's rabbit hole is, and thus did not inform bureau. She is informed that Gina Zanetakos has escaped. The FBI men collect all the evidence that she has on Tom.

Meanwhile, Tom checkmates a Red's man who has been tailing him. He asks the man to call up Red and tell him that he has lost the tail. Dembe informs Red that they have lost the husband. Tom beats the man black and blue. The man is of no use to Tom, as he does not know anything about Red and his business though the man claims to know everything. Tom reveals that he has followed Red for years and thus knows his modus-operandi. He calls Red dangerous, careful, cautious, and ruthless, but adds that his boss is more cautious, far more controlled and ruthless. When the man tells Tom that he should be working for his boss, Tom says one does not choose Berlin, but Berlin chooses the person. "And, he is coming," Tom says to the man. There is a tattoo of spider on the man's neck and Tom couriers the tattoo to Red.

Red is sitting in Cooper's office when Liz arrives to give her letter of resignation to Cooper. She wants an immediate transfer out of the task force. Liz ignores Red's repeated attempts to communicate with her. He has an urgent case. Liz tells Cooper that she is only valuable to the bureau because she is willing to speak to Remington and now that is not going to happen. Cooper also gets to know that Red killed Liz's father. Red refuses to leave the room, and tells Liz that the case is related to her husband and there is an imminent danger. Cooper wants to know if it is related to Berlin. He had picked a piece of paper, with Berlin written on it, from Liz's board at her storage unit. Red warns that people are going to die. Liz is not ready to communicate and says that those lives are in Red's hands. When Red says if she is going to put her anger at him above the lives of innocent people, Liz has to re-consider her decision and do the case. But, it will be the final case as per her.

Red updates Liz and the FBI about what happened at the bank, and says that the cause of death may have been the lethal Cullen virus. He believes that the man may have been infected as part of a larger plot that involves Red and the task-force. He adds that the incident is a biological threat and part of a coordinated attack plan, which is directed at him. He calls the dead man a foot-soldier in a biological army, which aims to cause global pandemic. Red warns that the person behind the plan does not care how many people die as long as Red is one of them.

Liz and Agent Ressler get to know that no one else was infected at the bank, as the virus was not airborne and was designed to only affect the victim. If it had been airborne, thousands of people would have died. There are only a few who know how to mutate this virus, and whoever is doing it is not doing with a good intention.

Red knows a person who knows all about black-market viruses. To get information from that person, Liz is with Red in his private plan, but is in no mood to exchange words with him. Red gives her a decoded copy of Tom's advanced calculus book, which has little information about Red and his organisation but a lot of information about Liz and speculations about their cases.

Meanwhile, the FBI team discover that the syringe found on the dead man contains the anti-dote, and not the deadly virus. This surprises Cooper as the CDC said that there was no known cure. The text messages derived from the dead man's cell indicate that the dead man was supposed to do a job on the 30th if wanted the next dose of the anti-dote. It turns out to be a case of extortion and Agent Ressler figures out that the man chose to die, rather than follow the orders. Cooper point out that there is likely to be a replacement for the dead man.

There is a replacement, as another man appears showing the same symptoms. He switches on his laptop to see a video message for him. The man gets to know that he has been infected with the most deadly Cullen virus and that he is going to die, if he does not do as ordered. He finds a syringe that contains his first dose of anti-dose, which will sustain him for the next 24 hours.

Red and Liz meet Dr Sanders, a patient at a mental facility hospital. He tells them that the five horsemen are coming and who will bring death and destruction, and mentions about a space agent, UD 4126. Red and Dr Sanders talk abstract stuff and Liz walks out. She accuses Red of planning the trip so that he could change her mind. Red gets to the main topic, the virus, but Liz wants to know who is plotting the whole thing. Red has no clue about that. Liz walks away from him after asking if there has been a single selfless moment in his entire life. She flies back on her own.

At the Cooper's office, a man informs Cooper that if Liz quits, the deal is off with Red and he will not have any immunity. Red will be arrested and not see sunlight, again. There is trouble for Liz, as well, because of both Red and Tom. The man wants to talk about how they could bring Red in.

Liz returns to her FBI office to find that Red has send research notes of Dr Sanders. Liz is surprised to know that Dr Sanders has worked on the theories for the Cullen anti-dote. Agent Ressler wants her to go back to the doctor and find out about the person who was helping him from the outside, as the development of the anti-dote needed a lab outside of the mental facility. Liz has no other option but to approach Red for help when Dr Sanders refuses to talk to her. She tells Red that they are still not on talking terms. Back at the hospital, Dr Sanders keeps repeating that it is UD 4126 who contacted him while Liz wants to know the person's name and identity. Dr Sanders gets hyper and an attendant tries to calm him down. Liz sees that attendant's badge and something clicks. She exits the hospital, without telling Red anything.

At the FBI post office, Aram goes through the badge of various organisations and informs Liz that the only organisation that uses UD as prefix on its badge is CDC. He also finds out the identity of UD4126. It is Dr Nikolaus Vogel. The FBI team arrests the doctor from his home, and they also find evidence to nail him. Dr Nikolaus, however, refuses to answer of any question. He just says that "he is coming." Afterwards, Liz gets to interrogate him solo. She uses his trick -- infecting him with the virus -- to make him talk and give the names of the five people who he has infected with the Cullen virus.

Liz uses Tom's calculus notebook and the case files to discover that the blacklist cases -- not all of them -- can be traced back to one entity, Berlin. Agent Ressler feels that Red is using the FBI unit to eliminate the competition. Liz says to Cooper and Agent Ressler that they need to think like Red. She believes that it is not only the FBI who is after Red but there is someone else, too. According to Liz's theory, Red is unable to stop this person on his own and thus he gets the FBI on his side, and uses its resources and protection to survive, and it is not about expanding his empire. Liz guesses correctly that Berlin is not a place but a person and he is coming for Red that day.

Dr Nikolaus spills out the details about about the persons who have been infected with the deadly virus. These people have connections with airports in the area and are the five horsemen. Dr Nikolaus does not know much about the mission. He just knows that it has something to do with a prison transfer. The FBI team figures out that it is related to jail break, and not an outbreak.

Liz wants to take back her resignation, but Cooper informs her that it has already been accepted. She is worried and runs off to meet Red. Meanwhile, Aram shows a video of Dr Nikolaus to Cooper. He is talking about the tasks that the victims have to complete to get the next dose of anti-dote.

The victims' tasks include helping Berlin's associates take advantage position at the airport, and helping a prisoner, arriving in a prison transport plane, to escape. One of the victims is a pilot and he shoots down his co-pilot and takes control of the prison transport plane. There is a hooded man in the plane and the pilot is taking orders from him. The pilot throws the keys of the handcuffs to him. The FBI team storms the airport, which makes Berlin's associates kill the victims and get away in their armoured vehicle. The plane too does not touch the runaway and flies-off. A fighter jet shoots at the prison transport plane and one of its wings catches fire.

Liz tells Red to come with her, and get in the car, as Red's deal with the FBI is off and he does not have the immunity. Red isn't moving from the place until Liz tells him why the sudden change of heart. He knows that the FBI is coming after him. Liz is not forgiving him for Sam, but she needs answers and only Red can provide her those answers. Red says that he cannot find his answers without her, and according to Liz, this means they are both stuck with each other. The men from FBI's task-force surround him and he takes out his gun.

Red tells Liz about the time when he was stung by a lionfish while free diving in the Andaman sea. At the time, he was nursed back by a lovely sea gypsy. She kissed him, and Red tells Liz that it felt like a "burst of sunlight on my cheek and it made nearly dying well worth it. That's how I feel right now."

Red kneels down, gives Liz his gun and surrenders, putting his hands behind his head. Red sees the plane, with its wing on fire, fly above him. It crashes into the East river. Red says: "Now it begins."

It is beginning of the end of this season. The first part of "Berlin" solved a couple of big puzzles, why Red had surrendered and what was the blacklist all about. Through the men and women on the blacklist, he was trying to find the identity of the man who was slowly destroying his empire and trying to eliminate him.

The first part of the two-episode finale does not reveal who is Berlin, or provides an answer to what is Berlin's motive, but it builds up the suspense and there is dramatic tension. The penultimate episode of "The Blacklist" has set the base for an explosive finale.