James Spader plays Raymond Reddington in a scene from "The Blacklist." THE CANADIAN PRESS/AP, NBC, Virginia Sherwood

TORONTO - Megan Boone says James Spader's intense performance "sets the tone" for thriller series "The Blacklist."

As rookie FBI profiler Elizabeth Keen, Boone shares many dramatic scenes with the celebrated actor. She said his gripping portrayal of criminal mastermind Raymond Reddington inspires others on set to take risks.

"James doesn't really work in the obvious way, or inside the box. So it helps to have that in a room with you, because it gives you permission to kind of colour outside the lines and do things that are unexpected," she said.

"I think that's what keeps a series like this interesting week to week because, despite the formula of finding the Blacklist, we still have very surprising elements. People are doing things in an off-kilter way. And he really sets that tone."

The crime drama has been a runaway hit for Fox and Global since premiering last year. Reddington, better known as Red, promises to help the FBI capture the Blacklist — a roster of impossible-to-catch bad guys — on the condition that he is helped by Elizabeth.

As the series progressed, it was revealed that (spoilers ahead) Red has a personal connection to Elizabeth through her adoptive family. And her seemingly mild-mannered husband Tom (Ryan Eggold) — posing as a fourth-grade teacher — was actually a spy and assassin working for Red's nemesis Berlin.

When "The Blacklist" returns for its much-anticipated second season Monday, there will be even more surprises in store, said Boone.

"We have a sort of 'box in the floor' moment in the opening of season two and we spend the whole season uncovering that secret," she said in an interview earlier this summer.

The "box in the floor" is a reference to a box Elizabeth found in her apartment containing money, a gun and fake passports, all with Tom's photo — her first clue that her husband was not what he seemed.

While viewers were kept guessing about Tom's true identity, Boone says she revelled in knowing the twist.

"I knew what was going to happen with Tom in the first season. That made it completely fun in the first half of the season because everyone was constantly like, 'I know he's bad!' or 'No, he's good!'" she said with a chuckle.

"On the one hand I didn't want to break everybody's little hearts, but on the other hand I was like, 'We have a surprise in store for you.'"

In the season finale, Tom took Elizabeth hostage at gunpoint in a bid to force Red to surrender. But she managed to disarm him, shooting her husband three times in the stomach.

It's unclear whether Tom is dead or alive — and the actor who plays him isn't going to spill the beans.

"Tom might be dead in some warehouse right now. But he may be alive. If he's alive, there's going to be a really interesting area to explore," said Eggold, also speaking in a summer interview.

Eggold, 30, said he always knew that Tom was a spy. But he said he still has questions about Tom's history that he expects to be explored in the second season — among them: "What's his plan?" and "What is his relationship with his wife now?"

It's an interesting challenge to play a character who's leading a double life, he added.

"I try to, when I play Tom as undercover, be completely earnest and sincere in that character. He's had two years to perfect the role, so to speak, so he's probably good at it," he said. "And when we're in the questionable place, that's really fun because you get to play the question mark."

Meanwhile, many viewers have speculated that Red will be revealed to be Elizabeth's father.

Fans will get a deeper sense in the second season of "why Red is in Elizabeth's life," Boone said cryptically.

"His intentions might not be what we thought," she said. "I think the interesting thing about Red Reddington is that he's always got an agenda. Everything he says and does is about that agenda, including holding Liz up to be this very special person to him. You never really know whether or not to trust him."

— Follow @ellekane on Twitter.

News from © The Canadian Press, 2014