The 3:10 to Yuma scribe said that the film will pick up four years after its predecessor and see James McAvoy's Wesley Gibson recruit a young female assassin.
"The only thing I can tell you is that Wesley is now, four years later, recruiting a young woman who is in his situation in the first movie," he told Hollywood.com.
"She's got a sh**ty life. He's sort of in the Fox role. This new girl is brought into the world."
Abraham Lincoln: Vampire Hunter helmer Timur Bekmambetov is attached to direct the sequel based on a script by Haas and Michael Brandt.
The original Wanted, based on a comic book by Mark Millar and JG Jones, starred McAvoy and Angelina Jolie. It raked in $341 million (£212.9m) at the global box office, on a budget of just $75m.
Wanted 2 is yet to receive an official release date.
Watch a trailer for Wanted below: