“The Blacklist” Season 4 will shed light on a number of things, including Red (James Spader) and Liz’s (Megan Boone) history.

One of the biggest mysteries of the NBC series is Liz and Red's real connection to each other. In addition, the true reason behind Red’s interest in Liz also hasn’t been revealed yet. According to Boone and “The Blacklist” executive producer Jon Bokenkamp, however, Season 4 might be the installment where it all comes to light.

In “The Blacklist” Season 3, Liz faked her own demise, hoping to escape from all the dangers plaguing her and live a normal life with her partner Tom (Ryan Eggold) and their newborn daughter Agnes. They’d almost gotten away with it, had Alexander Kirk (Ulrich Thomsen) not managed to trace Liz’s whereabouts and abduct her. The fact that Liz turned out to be alive wasn’t the only big twist last season, however, since it turns out Kirk is her long-lost biological father. For those who are still in doubt about whether or not Kirk is telling the truth, Bokenkamp told Entertainment Weekly, “We should take him at his word.”

Kirk’s revelation is only the first of many truth bombs to come, according to lead star Boone. His appearance will also result to Liz finding out more information about her mother (Lotte Verbeek) and her connection to Red.

“Through the investigation of Alexander Kirk, she finds a lot of her mother’s memorabilia and private journals. A lot is revealed to her about her mother, who she’s known nothing about her whole life, and through her mother, she learns actually a lot more about Reddington,” she told the publication.

Even Boone herself has no idea how Red and Liz are connected to each other. In fact, only a select few know the truth: Spader and the series’ executive producers. “I never really felt like it was useful to me to know anything about the relationship that Liz has with Red, or about Red’s history and why he takes such an interest in Liz, because Liz doesn’t really know. I always wanted to maintain that mystery for myself. That being said, I don’t really know, maybe James Spader, Jon Bokenkamp, and John Eisendrath are really enjoying keeping it a secret from everyone,” she explained.

As more and more details about her past are uncovered, Liz will also stumble upon a shocking truth that could make her realize normalcy was never an option for her. “What comes to light is that it’s not really Reddington bringing all of this upon her, it’s her own history and where she comes from. Something you start to realize through Season 4 is she was strapped with this from birth,” Boone added.

Another person whose motives are a mystery is Kirk. According to the actress, the real reason why he searched for Liz and abducted her will be revealed very early on in the season, and it’ll be another big twist that fans can look forward to.

“It’s very complicated and it’s something that actually gets revealed — it’s a big reveal in episode 3 of Season 4. Like a lot of the people that crop up in our show, his agenda is not necessarily altruistic. He doesn’t have the best of attentions,” she shared.

Meanwhile, Spader recently made a guest appearance on “The Tonight Show With Jimmy Fallon” where he shared a special sneak peek of “The Blacklist” Season 4, episode 1, titled “Esteban.” Watch the teaser clip here.

“The Blacklist” Season 4 is set to premiere on Thursday, Sept. 22 at 10 p.m. ET on NBC.