The Source Material gang is back to review "The Coldest City." In 2012, Johnston wrote The Coldest City, an original hardback graphic novel in the Cold War espionage genre, intended to be the first in a series of books all set in Berlin during the Cold War. A prequel, The Coldest Winter, was released in 2016. Both titles were published by Oni Press. At the Cannes Festival 2015, Focus Features announced they had acquired North American distribution rights to The Coldest City, starring Charlize Theron and directed by David Leitch. The film, retitled Atomic Blonde, premiered in March 2017 at the South by Southwest festival.