The writer told Collider that previous mini-series Children of Earth was being used as "the template of the new Torchwood."
"Children of Earth left things almost format-less," he said. "They had no base, no authority and no mission... except to survive. They're very much underground [now] and trying to survive. They've taken extreme actions. They have friends, they have enemies and they have betrayals."
He continued: "We've got one script and very concrete storylines, so we know there are new regulars, new occasional guest stars and relatives of those characters."
Davies also confirmed that The New World would take place two years after the events of the previous series.
"Torchwood will have been off-air for two years, so I think it will feel like two years have passed," he explained. "The script isn't that specific about it, but I think that two-year gap feels right."
He added that plans to shoot on location in Los Angeles were "yet to be confirmed".
"Any place can double up as a number of places," he suggested. "There will be scenes set in Washington, certainly, but we won't go to Washington to shoot."
Torchwood: The New World is expected to air on Starz in the US and on BBC One in the UK next summer.