[2] For his first operation back with the Central Intelligence Agency, Court Gentry is tasked with capturing Fan Jiang, a former member of PLA Unit 61398, an ultra-secret computer warfare unit responsible for testing China's own security systems, through his former handler Sir Donald Fitzroy, who was contracted by the Chinese government for a similar operation, in Hong Kong.

Their principal boss from the Ministry of Defense (MOD), Colonel Dai Longhai, becomes frustrated about this routine surveillance op and orders them to eliminate Gentry, who instead manages to kill them.

Aware of his reputation as the Gray Man and his past relationship with Fitzroy, but unaware that Gentry is working on behalf of the CIA, Colonel Dai hires Court to find Fan and eliminate him.

After a violent bar fight, he finds out that Fan had in fact escaped to Vietnam and is now under the protection of the Con Ho Hoang Da (Wild Tigers), a Vietnamese criminal organization.

However, Zoya's team was one step ahead of Gentry once again, as she determined the compound to be Fan's hiding place from interrogating a Vietnamese police officer who was on the Wild Tigers's payroll.

Her team infiltrate the compound that night, which turned into a full scale gunfight with the Wild Tigers, as well as soldiers from the People's Army of Vietnam (PAVN) who were there as extra protection for Fan.

Now desperate and wanting to salvage her mission on her own, Zoya tries to recruit the services of the Chamroon Syndicate, a Thai criminal organization, but is later burned by the SVR for not reporting in to her employers sooner.

When his parents died in a car accident, leaving him with no family members and making him liable to be executed according to the "family collateral" rule among members of unit 61398 (hackers with no next of kin are deemed untrustworthy by the government), Fan was helped by his parents's guardian Song Julong, later deduced by Court to be a double agent working for the CIA, in defecting from China.

He originally wanted to go to Taiwan through Hong Kong with Taiwanese papers provided by a contact of Song's, but he was left behind in the border when Colonel Dai's men chased him.

Once again impatient, Colonel Dai orders his men, led by his second in command Major Xi, to storm the nightclub in pursuit of Fan and Chamroon's senior leadership.

They were put in a ranch house, where the colonel tells Court that he himself will supervise the attack into the Chamroon estate, and that he and his Russian girlfriend will stay behind until the operation is over.

Court had made contact with Brewer and tells her to abort the CIA Ground Branch's impending raid on the estate, which would have led to a violent gun battle between them and Colonel Dai's forces as well as an ambush from Chamroon's men.

[5] Carol Memmott of The Washington Post said: "Fans of RPG, Hong Kong action films and high-octane storytelling will love the Gray Man, who battles full-bore through this fast-paced series.

"[6] In a starred review, Publishers Weekly hailed the novel as "outstanding" and added that "Gray Man fans will close the book happily fulfilled and eagerly awaiting his next adventure.

"[7] Prominent literary reviewer The Real Book Spy remarked: "From start to finish, Gunmetal Gray impresses with a well-laid-out plot and enough action to satisfy even the pickiest thriller fans.