Episode 21 of the second season of The Blacklist begins with Red feeling worried that Karakurt would be planning several attacks on the American defense installations.

Karakurt is the Russian assassin that was smuggled into the country by Cabal in episode 20, and it is likely, to Red, that he is planning to trigger another Cold War.

Liz seems more concerned, though, with learning more about her mother.

Later, Liz goes with Ressler to a Russian intelligence compound.

Here, she hopes to kill two birds with one stone, by getting some information on Karakurt, as well as finding something on Liz' mother.

At the same time, Red was torturing a man whom he suspected of helping Karakurt set himself up in America.

He got some information, including that Karakurt was planning to use a truck to bomb an intelligence target.

The target was the compound that Liz and Ressler had just left, and the explosion killed 12 agents who were inside, shortly after their departure.

The FBI rushed to find out what Karakurt's next target would be.

Meanwhile, Red got a tip that Karakurt had been seen at an apartment that he had searched before.

But, Tom Connolly continued to blackmail Cooper, which forced the director of the FBI to send Liz and Ressler to Union Station, instead of the apartment.

Liz was attacked at Union Station, but she was not able to apprehend the assailant. She suspected that he was Karakurt, but she could not be sure.

The FBI discovered a biochemical lab in Karakurt's apartment and found that he created a virus which could be transmitted by skin to skin contact.