In the film, it is intelligence, rather than physical prowess, that becomes Heller's main weapon. In one gripping scene, he confronts a man involved in his wife's murder. Instead of resorting to direct violence, Heller cleverly uses a remote device to shatter the glass of a suspended swimming pool — positioned 35 meters above the ground as a bridge between two buildings — sending the villain, who is taking a night swim, plummeting to his death.

For director James Hawes, it was a challenge to make changes to the original novel, which is set more than 40 years ago.

"The nature of espionage has changed dramatically. The whole political landscape has shifted. One example is that in the novel, most of the action takes place in Prague in today's Czech Republic, which was known as 'a city of spies' before the Iron Curtain came down. But that isn't the case anymore," Hawes tells China Daily.

Istanbul — a vibrant, historic city that straddles Europe and Asia — thus becomes the alternative setting for some of the most pivotal scenes.

"We wanted a city that feels more like it is on the edge of Europe …Istanbul is not often seen on screen. It's on the border between the East and West. It's just that bit more edgy, exotic and exciting," he says.

As an action-packed tentpole with a globe-trotting storyline, the film was also shot in London — the city's St. Pancras International train station features in the scene of Sarah's death — as well as in Paris and Marseille.

With scenes purportedly shot at the CIA headquarters in Langley, Virginia — a location that has been featured numerous times in films and TV series — Hawes was careful with the details and employed security advisers throughout the production.

After learning that London has one of the highest densities of surveillance cameras per person in Europe — exemplified by data showing that the average person is photographed up to 300 times each day — Hawes says this fact makes one scene more credible. In it, the protagonist takes advantage of the extensive surveillance system by tampering with real-time footage, copying his face onto multiple individuals to create the illusion that he is in several locations at once.

When asked what he believes will be the film's most appealing element for Chinese cinemagoers, Hawes replies: "It's all about the power of the underdog. I think Rami did so well to show him (Heller) sometimes failing but always fighting back. I think audiences love an unexpected hero."