The following contains spoilers for The Gray Man, now streaming on Netflix.
Netflix's The Gray Man painted a globetrotting, bullet-ridden extravaganza as Ryan Gosling's Sierra Six went on the lam. He uncovered data incriminating his new CIA boss, Denny, in terrorist activity, so Chris Evans' Lloyd Hansen was designated with retrieving him. The Russo Brothers, along with their Marvel Cinematic Universe collaborators/screenwriters, Christopher Markus and Stephen McFeely, backed Six into a corner, evoking many movies in the spy genre. However, as a resilient Six found allies, the movie deviated quite a bit from Mark Greaney's 2009 novel of the same name.
Six Was on the Run for a Different Reason
In Greaney's The Gray Man, Six was a wanted man before the narrative kicked off. After killing Nigerian President Julius Abubaker's brother, the company conducting natural gas deals with Julius, LaurentGroup, was tasked with taking down Six. If not, Julius wouldn't engage in business. Six's past with the CIA wasn't even in focus in the first book, as he was painted as an agent who worked for Fitzroy under an English private security firm, Cheltenham Security Services. Instead, the Russos tackled what caused his exile, which later stories from Greaney would address. This allowed the Russos to have Six and Fitz form a fatherly bond for almost two decades, rather than just being colleagues for a few years in the first book.
The Gray Man Movie Turned Lloyd Into a Military Man
In the novel, LaurentGroup hired Lloyd to kill Six. He was a former CIA officer, but he eventually became a lawyer, using his network to recruit various assassins. But this is quite different from the movie, which made Lloyd more hands-on and aggressive. The Russos had Lloyd as a member of the CIA who got kicked out for being uncontrollable in the field, only to be reactivated by Denny to get the data from Six. The torture-loving Lloyd was modeled after the book's Kurt Riegel, a deadly German operative.
Dani, Margaret and the Lone Wolf Are Original to the Netflix Film
Ana de Armas' Dani Miranda was made just for the Gray Man film. She was a CIA handler who realized Six was being targeted by the corrupt Denny. She helped him out on the mission, forging that rare human bond Six lacked in his life. Eventually, she'd aid in taking out Lloyd's men in Croatia in the finale before going back to the CIA to ensure Six didn't go to jail due to being framed. In the novel, Six did get help from a French nurse during one mission, which is as close as he got to having a Dani.
In the Gray Man movie, Six and Dani went to Prague to meet Margaret Cahill, a former CIA associate who worked with Fitz and Six. She helped them decrypt the hard drive in the present, but moments later, she died in a brutal firefight, buying the duo time to escape. The novel, though, didn't have her, but it did have Maurice -- the man who trained Court after he got out of prison for the CIA and offered him safe haven at the end of the book. In the film's case, Maurice's role was split between Margaret and Fitz.
Lloyd's main assassin in the Gray Man film was a Tamil soldier nicknamed the Lone Wolf. He brutally beat up Dani and Lloyd, stole the data and took it to Lloyd. However, when he realized Lloyd was going to kill Claire, he gave the data back to Dani, citing his honorable moral compass. This didn't happen in the book, as Lloyd used a more straightforward hunter in the form of Song Park Kim, a Korean hitman who was all business and lacked the Wolf's sympathy.
Lloyd Took Different Hostages
The Gray Man novel had Lloyd kidnapping Fitz's son and grandkids, with only Claire surviving the onslaught. She and Six would then bond as he tried to get her back to Fitz. The film changed this, with Claire being Fitz's niece, someone he looked after following the death of her parents, and someone Six babysat in Brazil. The movie then had Lloyd kidnapping both Fitz and Claire to lure Six out of hiding, making it more of a story about a CIA civil war rather than LaurentGroup against Cheltenham.
The European Action Was Different
The Russos' Gray Man movie went to the Czech Republic and France, but it omitted other key locations from the novel: Switzerland and Iraq. In addition, the movie's big Fast & Furious scene -- a firefight in Prague outside Margaret's home -- wasn't in the novel. This was created for spectacle, as it involved a lot of explosions, a car chase and a train crash, all so Dani could save Six and reassert how much he needed her. Other action sequences that didn't make it into the film included Court fighting off assassins in a Paris alleyway and evading killers in the Swiss mountainside.
The Gray Man Movie's Ending Killed Fitz
The Gray Man novel had Claire helping fight off Lloyd's men as well, with Six eventually getting her to Fitz. This left Fitz relieved but eager to help Six destroy his enemies in later books by tapping into his past with MI5 (not the CIA). The movie changed this drastically in the showdown at the Croatian mansion when Six rescued Fitz and Claire. Fitz blew himself up, like Margaret in Prague, to buy the duo time. After Lloyd's mission fell apart, Six later escaped CIA custody, broke Claire out and went on the run with her.
Six's Origin Is Less Dark
The Gray Man movie revealed Six killed his abusive dad to save him and his brother when they were teens, evoking shades of Peacemaker and The Boys. In contrast, the novel had Six's dad training him in a SWAT school before they became estranged. The man was alive and well, but Six kept away because he hated his dad's toxic masculinity. Six still ended up in prison for Maurice to pluck and train, but in the book's case, it was for murdering three guys in Florida.
Denny and Suzanne Are Bigger Players
In the movie, Suzanne was an officer helping clean up Denny's mess, not realizing how corrupt he was. She ended up killing Lloyd, framing him for Denny's sins and then getting the CIA to cover everything up. However, Denny and Suzanne weren't in the first novel -- only in the sequels. There, they didn't even know each other, nor did they all go to Harvard together with Lloyd. In fact, Lloyd actually went to Princeton in the Gray Man novel, but one thing was constant: Denny's scheming was the real reason Six was being hunted.
See these changes from paper to screen in The Gray Man, now streaming on Netflix.