In the recently concluded episode of "The Blacklist," viewers have seen how the team mourned for the death of their colleague, Elizabeth Keen (Megan Boone). Her death also readies the stage for what is going to happen in the upcoming episodes. One of these is the introduction of Famke Janssen as a woman with a very dangerous past.

Janssen will portray the role of Susan "Scottie" Hargrave. Aside from her dangerous reputation, it is also revealed that Tom Keen and her have a history.

The official synopsis for the upcoming episode says that, "When Reddington (James Spader) links an elegant, powerful and extremely dangerous woman to the recent tragic events, the task force is forced to play a deadly cat and mouse game to stop her before she strikes again."

The voiceover heard in the promo trailer of episode 21 portrays Hargrave as the only person who can go "toe-to-toe with Red."

In another scene, Red is seen informing his team that "Scottie Hargrave will be attacking in multiple fronts." Then, another scene shows Red and Hargrave sitting and talking face-to-face with Red issuing a threat, "Elizabeth Keen is dead, which means you are, too." However, Hargrave seems unfazed with the threat showing that she indeed is such a formidable opponent.

Meanwhile, previous season finale spoilers indicate that someone unexpected will betray Red. According to spoilers, that man might be Dembe (Hisham Tawfiq), who is Red's most loyal and trusted man. It is evident, however, that Red has been giving Dembe a lot of attitude lately, especially when the latter asked him to come clean to Liz.

Aside from this, the season finale will also introduce a new villain named Alexander Kirk (Ulrich Thomsen), whom Red knew in the past. It is said that he holds a secret that could damage Red.

"The Blacklist" airs every Thursday at 9 p.m. EST on NBC.