These are the words spoken by the character in the promo video;
My name is Captain Jack Harkness, and I have seen the universe. But none of those endless horizons could prepare me … for what I found on Earth. I found a world convulsed by the Miracle. But it was far more than just a blessing on mankind. It’s part of a conspiracy dating back almost a hundred years.
I thought I could bring Torchwood back. I thought Torchwood could fight this thing and save the world. I was wrong.
Source [Doctor Who News]