After several weeks of silence, Raymond "Red" Reddington emerges from hiding tonight with a new episode of The Blacklist, the freshman NBC drama starring James Spader as a globally connected criminal who works with the FBI to take down the worst of the worst. While Red's true agenda remains unknown, this much is clear: The Blacklist is one of the breakout hits of the television season, with a massive audience and an early Season 2 renewal to back up the claim.

But what makes The Blacklist such a standout? Is it Spader's involvement? Is it the work of relative newcomer Megan Boone as similarly new FBI Agent Elizabeth Keen? Or is something far less tangible responsible for the show's success?

"Even before the show aired, it felt like it had luck shining on it," producer and writer John Eisendrath told Spinoff Online. "So much is about luck and timing. NBC being really supportive, Sony being incredibly supportive. … It's serendipity. You can have the greatest script, and it's just in the wrong place at the wrong time."

The Blacklist creator Jon Bokenkamp, who’s new to television, described the drama's success as "a breath of fresh air." Like Eisendrath, Bokenkamp can't pinpoint any one reason for why fans have flocked to the thriller, but he assigns much of the credit to the character Red Reddington.

"The barometer of Red, just in writing him, is the element of surprise," Bokenkamp said. "If something he's going to do, or the answer to a question, feels like a surprise to us in the writer's room, then that's probably the right answer. That's the guiding principle of Red. Right when you think you have him figured out, you don't."

"The leeway you get to write scenes for his character is incredibly enjoyable," Eisendrath added. "The things he says, his point of view, his outlook on the world — it's so strange and unique and enjoyable to write. It gives you the opportunity to explore so many things that are surprising, where other characters are a bit more limited."

But Spader wasn't the first cast member aboard The Blacklist. That distinction belongs to Boone, who won the role of the in-over-her-head agent in part because of her own newness.

"I think Megan, because she's somewhat new and fresh, just came in and had a vulnerability that felt really relatable," Bokenkamp explained. "That was an interesting and key part of why she connected with us."

"We'd seen a lot of actresses, and the minute she walked in and performed the first scene, there was an intensity about her and a capacity for darkness and being messed up that set her apart from some of the people we'd seen," Eisendrath added. "It was an organic part of Megan and an organic part of who the character is. It was a relatively easy call once we'd seen her."

Once the producers settled on their Keen, they needed to find their Red. But it wasn't a matter of selecting an actor who would pair well with Boone; according to Eisendrath, the process was a bit more primal.

"Casting for a pilot is mostly desperation," he laughed. "It wasn't that once we got Megan, we narrowed it down to who would be a good person to play opposite her as Red — we were just looking for anybody who was a) great and b) willing to do it. We were incredibly lucky to find someone who was both in Spader."

In their search for Red Reddington, Eisendrath and Bokenkamp were turned down by numerous actors, in part because "a lot of actors would rather do cable and only want to do 12 episodes." Spader was game, and the producers couldn't have been happier. "We cast him only three or four days before we were going to film," Eisendrath recalled. "It's another example of this show being one of those shows that's incredibly lucky. He was a late casting choice, and when we look back on it, it's like, how could we have cast anyone else?"

As Red and Liz, Spader and Boone shoulder the bulk of the show's weight, carrying the core story and mysteries forward. Eisendrath credits a portion of the characters' chemistry to how their on-screen relationship mirrors the dynamic between Spader and Boone.

"James being someone whose done this for a long time, who has a great deal of experience and a great deal of confidence, is sort of played in a very interesting way against Megan, who is somewhat new," he said. "The first scene they had together was the scene from the pilot, where she stabs in him the neck. … When Megan showed up on set, she was ready to go, but she was rattled, obviously. She had a huge scene to do with this very well-respected actor and she didn't feel prepared. I think that plays into their dynamic."

Beyond Spader and Boone's dynamic, another reason why The Blacklist succeeds is its balance between procedural and episodic elements. By design, each episode features a different villain from Red's titular list of the world's deadliest criminals — criminals he will help the FBI to apprehend, as long as his terms are met.

"It feels like one of the reasons that people can wrap their brains around the show is because of 'the Blacklist,'" Eisendrath said. "Every week, there's a name on the list. There's a coolness to the people who qualify for being on that Blacklist. Just by definition, it elevates the procedural cases in a way that a lot of shows have a hard time doing."

But the "villain of the week" format doesn't come at the expense of ongoing mystery: There are several lingering questions the series continually teases and expands without fully answering. Red's connection to Liz is one such question; the true identity and allegiance of Liz's seemingly normal husband Tom (played by Ryan Eggold) is another. Bokenkamp said the writers have answers to many of these questions, but the path to the answers is less clear.

"We know big answers to some of the central questions of where we want to go," he said, "but how we're getting there. … We know the destination, but how we get there is the fun part of figuring it out. We're winging some of it, but we also know certain landmarks that we want to hit."

"With all of the questions — Why does Red want Liz? What's his interest in her? What's the story with Tom? — we've tried to answer those questions from the perspective of, 'What are the most emotionally grounded answers?'" Eisendrath said. "I think if you can give a really good and mostly grounded answer, it can be small and satisfying, certainly more so than a huge, big answer that isn't emotionally resonant and is just cool."

Given that philosophy, will the mystery of Tom, for instance, have a straightforward answer? Do the writers feel that if Tom doesn't have a double life, if he turns out to be nothing more than the school teacher he claims to be, it'll be a satisfying answer? Eisendrath was understandably cagey on the matter, saying, "I think the audience would accept it. I'm not saying that's what we're doing, but I think they would accept it."

The questions surrounding Tom's true intentions, and Red's own agenda, will continue as soon as tonight’s midseason premiere, titled "The Good Samaritan Killer."

"We're going to continue to deepen the bigger questions in the series," Bokenkamp said. "Two obvious ones being, in the short-term, who is Red looking for, and who does he think betrayed him [in the midseason finale]? Who's responsible for the incursion? And the bigger question is revisiting what Red said to Lizzie at the end of the last episode: 'Be careful about your husband.' We will dive into that question more when we return."

But there's more than the mythology-defining questions to consider as The Blacklist continues its first season. "We were rather serialized in the last couple of episodes," Eisendrath said, "and these larger questions aren't going away, but we will see some of these rather interesting, strange Blacklisters in the coming episodes as well."

The Blacklist returns tonight at 10 ET/PT on NBC.