At last Sherlock Holmes has met his nemesis, and it's not Professor Moriarty. It's a sexy dominatrix whose intelligence matches her beauty -- a steely foil for the famous detective.

Actress Lara Pulver dons that mantle when "Sherlock" returns Sunday to "Masterpiece Mystery!" on PBS in a modern version of "A Scandal in Belgravia."

The role was an actor's dream, said the British Pulver.

"It was a gift of a role, surrounded by everyone at the top of their game creatively -- from writing to directing to fellow actors, to cast and crew. ... It's really exciting," she said.

"When I was reading the script for 'Sherlock,' I was actually flying back from the U.K. to L.A., and I remember thinking ... we needed to turn the plane back around because it was just the best piece of writing that I'd read in a long time."

Occasionally great writing is not enough, she said.

"Sometimes, you put it together on paper and it's something exciting, but you put it together and it just doesn't quite work. On this occasion, the ingredients were so right to make this lovely cake."

The frosting on that cake is Pulver, whose two-minute nude scene in the show caused a sensation when it aired in Britain. She plays the seductive mystery woman as though she were born to it.

But Pulver admitted she's not so confident in life.

"I'm sure there are many things [that frighten me] but somehow I'm sure they all are, 'Am I enough?' As in, 'Am I good enough? Am I enough, just as a person? Am I enough for anyone, for myself for anyone, for me, for what I'm meant to be on this planet?' I guess then that is the fear of failure."

The actress, who started in theater and co-starred in "True Blood," "MI-5" and "Robin Hood," said, "If you take away the fact that I'm an actress, if you take away hair, makeup and clothes, is what you have left enough? Would you be attractive, or would you not be wanted, or would you be successful?"

A career can become your persona, and Pulver thinks that's a mistake.

"For me, it can't be your identity; it's unhealthy if it is. People will come up to you thinking they know you because they have seen you on their television screen or their movie screen or stage or whatever. I think it is about surrounding yourself, about being grounded by really healthy people of integrity and good hearts, and I pride myself in that."

Pulver, who grew up in Kent, recalls her parents' separation as a difficult time in her life. Last year, she went through her own divorce from actor Josh Dallas, who plays Prince Charming on "Once Upon a Time."

While that was a trying time, Pulver said she'd be willing to marry again. In fact, lately she has gathered the courage to indicate that.

"I just recently said to someone quite courageously, that -- a friend of mine -- and I said, 'If you ever wanted to, like, go on a date or something, I'm up for it.' I was brave enough to go, 'I like you. You are a nice person. We could go on a date and go, "What ... are we doing; we are good friends?" Or we could go on a date and find there is something there.' But I just said it. And I was really floored by myself."

Like her fellow Brits, she has a certain reserve.

"I would love to ask for what I want," she said. "'This is what Lara needs, and this is what Lara wants.' And If I don't get it, that's OK, but I [would have] managed to articulate it."

Pulver first came to the States when she was starring in the hit play "Parade" in London and it was transferred to a theater in Los Angeles.

"So I got this gift to come here for four months and be a part of that and I felt that I would come and see what happened here," she said.

"And it felt very much like I was putting everything in my work basket. I was coming here primarily for work, and then had to find my life around it -- make new friends and I had to do mundane things like sort out car insurance."

Adjusting required more than driving on the opposite side of the road.

"We speak the same language, but we sort of don't," she said. "Culturally, we are very different. And I think people will do that when they are 16; they will go to drama school in London or in another country or something like that. But to do it when I was 27, 28, was big."

Still, it proved a wise move.

"It made me more fearless," she said. "That was the moment where I said to myself, 'Lara, you have the freedom to live anywhere you want to in the world. It's OK. You stay a week, and if you don't like it, you move on.' The second I gave myself that freedom, it was a joy, and I ended up staying for two and a half years."