NEW YORK - If not for the absence of an all-important "o," Julianna Margulies might never have considered doing "Canterbury's Law." On this new Fox legal drama, she plays Elizabeth Canterbury, a fiery defense attorney who, after hours, is falling apart.

"She's dark, complicated, funny and screwed-up," Margulies says.

She might even overshadow nurse Carol Hathaway, the character Margulies played so impressively on "ER" from 1994 to 2000.

And though Canterbury practices law in Providence, R.I., "Canterbury's Law" was providentially shot in New York, where Margulies, 41, makes her home with attorney husband Keith Lieberthal and their seven-week-old son. No one could be more surprised than Margulies.

"There's been a lot of cosmic things going on in my life," she says with a throaty laugh during an hour borrowed from young Kieran for a midday omelet at a diner just a few steps from her Manhattan apartment. (The initial 6-episode run of "Canterbury's Law" begins Monday at 7 p.m. CST.)

After "ER," which kept her in Los Angeles and on-the-job isolation, Margulies had followed up with a variety of projects that were also shot almost anywhere but New York. Films included "Ghost Ship" and thriller-turned-punchline "Snakes on a Plane." She did miniseries like "The Lost Room" (sci-fi), "The Grid" (political intrigue), and the disturbing historical portrait "Hitler: The Rise of Evil."

Then, in 2006, a three-episode arc on "The Sopranos" turned her loose as Julianna Skiff, a New Jersey real-estate agent with a heroin habit and lousy taste in men. Guest starring on the celebrated New York-based mob drama left Margulies eager to return to TV with her own series.

"But I was looking for a New York show," she says, "and preferably cable." She reasoned that cable would call for fewer episodes per season, meaning higher quality and a less demanding schedule than with a broadcast-network series.

"Then I got the script for 'Canterbury's Law. I read it on a Saturday night." She liked it, and liked the fact that it was from Denis Leary and Jim Serpico, producers of "Rescue Me," the acclaimed series about New York firefighters that airs on the FX cable network.

"On Monday, I called my agent and said, 'I'll do it.'

"He said, 'But it's Fox.'

"I said, 'No, it's FX.' I looked at the cover letter again. Whoever it was who wrote it had left out the 'o.'

"When I realized the network was Fox," she says, "it was a tough decision."

Nothing against Fox, the broadcast sibling of FX. Margulies had just been recognizing the 22-episode grind of most broadcast series - in particular her six "ER" seasons.

"You can't make 22 home runs. On 'ER,' I used to think we managed a good 15 or 16 each season. But every now and then I'd go, 'Guys! Don't blow up the hospital again!'

"If I had known in the first place that 'Canterbury's Law' was a series for Fox," she declares, "I probably wouldn't have even read the pilot."

Thanks to that omitted "o" and other factors, she shot the pilot episode last winter. Terry Kinney and Ben Shenkman were among her co-stars, with the inventive filmmaker Mike Figgis ("Leaving Las Vegas," "Timecode") directing.

Right away, she felt comfortable in the role. And all the more so, thanks to her personal legal adviser: "I'd be reading the script and say to my husband, 'Honey, what's a voir dire? I don't understand.'

"I love this character," says Margulies, "because she's a tough character to like. She's stubborn. She drinks too much. She cheats on her husband. This isn't a woman who wakes up and starts the day fresh. She's bringing last night with her wherever she goes.

"And there's the backdrop of her having lost a child without closure. That helps the audience accept her behavior."

The little boy's disappearance is an unsolved mystery that haunts his mother. Margulies vividly remembers one heartbreaking scene when the series resumed production last August. It was a flashback years earlier to when he went missing.

"That was tough to do," she says. "I wouldn't have had the connection if I hadn't known there was a little baby inside me."

Shooting (and her harder-to-hide pregnancy) progressed. Amused, she recalls the many shouting matches between her character and Kinney as the district attorney, and with Aidan Quinn, Canterbury's mate in a crumbling marriage.

"I would go at it pretty hard with each of them, take after take," laughs Margulies, "and between scenes both of them would talk to the baby: 'We're so sorry, don't hate us. We're just acting."'

Then, back home, she would learn the next day's lines while channeling Mozart through headphones pressed against her belly.

Born Jan. 17, Kieran has a calm, happy personality, his mother reports. And now, as Margulies waits to see how "Canterbury's Law" is received - and whether she'll be facing 22 episodes next season - she seems happy, too.