Captain Jack Harkness (John Barrowman) - He looks like a hero, handsome, witty and subversive with a killer smile. But theres a reason for that glint in his eye, his dashing style hides a secret - Jack Harkness is immortal, the only one of his kind. He once ran the Torchwood Institute, a British organization dedicated to fighting Aliens and the bizarre. But Torchwood closed down, and Jack disappeared, to start yet another of his many new lives. When a new, epic danger affects the whole planet, Jack finds himself back at the center of events, fighting not just for his own life, but for everyone on Earth.

Gwen Cooper (Eve Myles) - She once lived the ultimate double life - the funny, salty, earthy woman who loves home and family, combined with the tough, ruthless warrior, who loves the thrill of the fight. She was the heart and soul of an organization called Torchwood. She was a defender of the human race. But now she lives in seclusion, with her devoted husband Rhys and baby Anwen, knowing that one day trouble would come calling again. When events surrounding Miracle Day push Gwen to the limit, she'll need to call on resources she never knew she had and make the most terrible decisions, on behalf of all mankind.

Rex Matheson (Mekhi Phifer) - He is the golden boy, the embodiment of the American dream and has been all his life. Harvard education, Rex is destined for success and could make a fortune in Wall Street or Hollywood, but he chose the CIA because he believes in justice and will fight for it. He can talk his way into anything, then charm his way out, fast. This may be just what he needs as he joins forces with Jack and Gwen to fight a global mystery behind Miracle Day that has them racing from one crisis to another, dodging assassins, blackmail, corruption and conspiracy, from Washington to Wales and the slums of Shanghai.

Esther Drummond (Alexa Havins) - An innocent, in a world of assassins, liars and zealots. She got where she is with the CIA through diligence and application. Hard work keeps Esther focused but she still dreams of active duty as a field agent serving her country. The dream is going to happen faster than she thinks and in no time at all, Esther finds herself running alongside Jack, Gwen and Rex, living off the grid, gun in hand, fighting a global conspiracy against enemies ranging from big business to the state. Its a tough, brutal, hard lifestyle where survival is hard won and life-changing choices have to be made.

Oswald Danes (Bill Pullman) - Well-educated and a former school teacher, Oswalds a convicted child killer, both guilty and unrepentant. But when Oswald survives his own execution, he is given a whole new life. The most infamous man in the world, he becomes the most provocative figure in modern media. Hes a flare, reviled yet mesmerizing, whose very existence embodies how the world changed on Miracle Day.

Doctor Vera Juarez (Arlene Tur) - An attending surgeon in Washington DC, shes smart, fast talking and hard working, Vera is on the frontline of medical care on Miracle Day. As the world crisis grows, Veras surgical and ER experience sees her recruited to advise on government think-tanks until she has to make a moral choice of enormous consequence. Sexy, confident and passionate, Veras life is soon inextricably tangled up with Rex's.

And six possible futher ones:

Clyde Maloney: Wannabe power stricken Hitler, Gender: Male, Age: from 40 to 50

Miss Jilly Kitzinger: Powerful, executive in the corporate community, Gender: Female, Age: from 20 to 40

Christina Colosanto: Very well educated, Gender: Female, Age: from 20 to 40

Lucy: Esther's sister, exposed, about to have a nervous breakdown, Gender: Female, Age: from 20 to 40, Ethnicity: African American

Alan Sweetman: A smart man, whom everyone likes, Gender: Male, Age: from 30 to 50

Young Angelo: Italian, emotional, very attractive, Gender: Male, Age: from 20 to 25