NEW YORK -- Lauren Ambrose is explaining what happens on "Torchwood: Miracle Day," her new Starz sci-fi series. Let's listen:
"An unnatural global phenomenon takes place where nobody is dying anymore. Our show explores the repercussions throughout the world. And I play the person who's there to sell it!" She beams. "This is a vicious and ambitious person -- a new kind of role for me!"
Indeed. As glossy, calculating PR pro Jilly Kitzinger, the 33-year-old Ambrose is making a colorful addition to the list of characters she has played since her acting career began two decades ago. With Jilly, she leaves behind forever the role for which she is most widely known, that of Claire Fisher, the hearse-driving, tormented teen on the HBO funeral-home drama, "Six Feet Under."
And, no, the irony is not lost on her: how she starred, before, in a series about dying, and now she's in a series where people can't die.
"Torchwood: Miracle Day," which airs its third episode on Friday at 10 p.m. EDT, is a spinoff of the much-adored "Torchwood," a British series that told of the Torchwood Institute, a mysterious organization dedicated to fighting the world's strangest, most sinister menaces. But Torchwood was shut down.
Then, at the beginning of this new series, a moment arrived on planet Earth when the dying stopped. The first instance: Oswald Danes (played by Bill Pullman), a murderous pedophile who proved impossible to execute. They couldn't kill him, so they set him free.
Lofted by the twisted logic of the modern media age, Danes was transformed into something of a rock star in the public's esteem. His image was revamped, in part, by Jilly Kitzinger, who called herself "something of a talent spotter" when she first approached Danes on last week's episode.
He had just appeared on a cable-news show, and Jilly was incredulous to learn that he didn't charge the network for his galvanizing interview.
"It was a NEWS show," he told her sourly. "They don't pay."
"That's very funny," she said, dissolving into laughter at his naivete. "That is positively hilarious."
Meanwhile, an intrepid team has coalesced to get to the bottom of the planet-wide scourge of immortality, which could rapidly exhaust the Earth's food and other finite resources. Back together are Torchwood veterans Captain Jack Harkness (played by John Barrowman) and Gwen Cooper (Eve Myles), joined by CIA agent Rex Matheson (Mekhi Phifer), CIA operative Esther Drummond (Alexa Havins) and Dr. Vera Juarez (Arlene Tur). They resolve to crack what they see as a global conspiracy.
"It's more than people surviving," says Jack on this week's episode. "It's as if some THING is willing them to go on -- each and every individual forced into life."
Is Phicorp the culprit? Turns out this pharmaceutical giant is plotting to profit from the tragedy. When people keep growing older without the prospect of recovery or death, they will need untold quantities of drugs just to manage their pain.
The ever-resourceful Jilly is representing Phicorp, too, and not a bit troubled by it. Phicorp can handle the crisis better than the government, she reasons: "FEMA is hopeless. It's a pot of glue that still thinks it's a racehorse."
"Torchwood: Miracle Day" challenges conventional wisdom (that death is a cruel interruption of life), and does it in ways that are sometimes graphic or downright macabre.
"After I watched some of the episodes, I was having really strange dreams," Ambrose confides. "I remember waking up and thinking, 'What a relief that that isn't our reality, and that we can find peace in the grip of death."'
But even as the series grapples with big ideas -- the very idea of a fate worse than death! -- its rollicking pace keeps things full of life. It's an action romp.
"There are things blowing up," reports Ambrose. "I get to do stunts in the show, and get in fights -- but I don't know how much I'm allowed to say. I get to run out of -- well, I can't say what! But I get to do cool stuff I had never done before. And wear superfancy couture clothing and have my nails done," she adds with a laugh and a toss of her lustrous red mane.
A native of New Haven, Conn., Ambrose made her off-Broadway debut at age 14 and her first movie appearance in the 1997 Kevin Kline-starring comedy "In & Out," followed soon after by "Can't Hardly Wait."
Other film credits include "Where the Wild Things Are," "The Other Woman" and the HBO film "A Dog Year."
On stage, Ambrose starred in the 2009 Broadway revival of Eugene Ionesco's "Exit the King," opposite Susan Sarandon and Geoffrey Rush. She also appeared in Sam Shepard's "Buried Child" at the Royal National Theater. And she played Juliet in "Romeo and Juliet" and Ophelia in "Hamlet," both for the New York Public Theater's Shakespeare in the Park.
She recalls doing Shakespeare "the most cared-for as an actor I've ever been. Fall, and the words will catch you in a big net!"
A former voice and opera student at Boston University Tanglewood Institute, Ambrose sings pop standards with the Leisure Class, her seven-piece combo of musicians based in the Berkshires in western Massachusetts, where she lives with her family: photographer Sam Handel, whom she wed in 2001, and their 4-year-old son, Orson.
All in all, Ambrose seems refreshingly grounded and unpretentious. But she credits performing for helping her stay balanced.
"I need to have an outlet," she explains, "and so I go and make up characters, and act and sing and dance like a crazy monkey clown." She smiles. "Then my brain is a little bit better."