The Russo brothers can't get enough of that gritty spy action.

After helming Captain America: The Winter Soldier, among the highest-grossing and best-reviewed blockbusters of the year, Joe and Anthony Russo are doubling down on the spy genre by taking on Sony Pictures' The Gray Man, based on the Mark Greaney novel of the same name.

Greaney's series of thrillers focuses on Court Gentry, an assassin on the run from enigmatic enemies. He has to combat them as he tries to save his daughters, who have no idea he exists.

“We found the material to be very compelling and ultra realistic and has a great character at the heart of it,” Joe Russo told Variety. “We are most interested in stories that are entrenched in the most modern elements that go on today and we think this book does an amazing job at explaining that.”

“We think this could be the next ‘Bourne Identity’ movie series,” added producer Joe Roth. “The Russo brothers are the most dynamic filmmakers working today.”

The Russo brothers are also set to direct the next Captain America movie, due in theaters in May 2016.