Rainbow Six is a techno-thriller novel written by Tom Clancy. It focuses on John Clark, Domingo Chavez, and a fictional multi-national counterterrorist unit codenamed Rainbow, rather than Jack Ryan and national politics. There is a series of video games by the same name.
Several NATO countries have collectively organized an elite counterterrorist unit, composed of the best soldiers from the militaries of several nations, named Rainbow. Based in Hereford, England (real-life home of 22 SAS, the UK special forces unit), the team is led by John Clark (who had the idea for Rainbow), a recurring character in Clancy's novels. Rainbow is "blacker than black," its American funding directed through the Department of the Interior by Congress, then through The Pentagon's Office of Special Projects, with no connection whatsoever to the Intelligence Community. Fewer than a hundred people in Washington, D.C. know that Rainbow exists.
The idea for the title comes from the United States color-coded war plans, specifically the Rainbow plans of the 1930s, where Rainbow Five is the last known plan. In these plans, various countries were given a color code, and the Rainbow Plans outlined strategies for dealing with potential conflicts between coalitions of countries. Rainbow Five, for instance, which is discussed extensively in the Plan Dog memo, details several U.S. strategies for America's involvement in World War II. For Rainbow Six, the aggressor is international terrorists. "Rainbow Six" also refers to John Clark, the leader of Rainbow, because 'Six' is often a designation for a leader or director. Additionally, the title symbolizes the multi-national nature of the elite unit. While a rainbow contains many colors, the unit contains many nationalities.
In a prelude to the story, Clark, Chavez, and Alistair Stanley (a former SAS operative and second-in-command of Rainbow after Clark) are on a plane bound for England. They foil an attempted hijacking of the plane by rather amateurish Basque terrorists; a take-down made easier by their government licenses to carry concealed weapons on an international flight. Immediately after landing at the nearest airport with the captured hijackers, the three leave the plane to take another flight before the media arrive, to avoid compromising the secrecy vital to Rainbow's future effectiveness.
Upon arriving at Hereford, Clark and Chavez are introduced to their new team. Both are still technically under the employment of the CIA, but they have been given simulated military ranks appropriate to their positions within Rainbow. Clark has assumed the rank of at least Brigadier (1-star) General as Rainbow Six, and Chavez, as Team Two leader, assumes the rank of Major. Neither man had been an officer during their respective military careers, so it is with a sense of irony that they accept their new rank and position. While Clark is not exactly thrilled at the idea of being a "suit," Chavez becomes quickly acclimated to the meticulous physical, tactical and weapons training that Rainbow field personnel go through. The result is a highly effective and cohesive pair of squad-sized operational units, supplemented by in-house intelligence and technological experts.
Not long after the establishment of Rainbow, a bank in Bern, Switzerland becomes the site of a hostage situation, eventually determined to be led by wanted terrorist Ernst Model. In an early and desperate show of resolve, the terrorists kill one of the hostages, leading to the Swiss government's request for help from Rainbow. Chavez's Team-2 is deployed to the scene, and disguised as Swiss "Polizei", is able to successfully breach the bank and kill the terrorists with no further loss of hostage lives.
Within several weeks, Chavez's team is again deployed, this time to Austria, where a group led by known German terrorists, Hans Fürchtner and Petra Dortmund have taken over the home of a wealthy Austrian businessman. Their mission is to kidnap the businessman, Erwin Ostermann, in order to obtain the special access codes to the international trading markets. The codes, they believe, are the secret to Herr Ostermann's success and affluence and that of his wealthy capitalist peers. Through careful planning and negotiating, the terrorists are persuaded to take their hostages out to a waiting helicopter, presumably to make their getaway. As the terrorists leave the house and make their way to the helicopter, Rainbow's shooters ambush and kill the terrorists. Again, the team was disguised to hide the true nature of Rainbow.
A third incident materializes rather soon after. Terrorists take over Spain's WorldPark, a fictional Disneyland-type theme park, taking thirty-five children hostage. They demand the release of Carlos The Jackal along with a list of other political prisoners. Due to the size and scope of the operation, Rainbow deploys both teams in response. During the stand-off, the terrorists execute a hostage—a terminally ill Dutch girl. Rainbow cannot prevent the execution because their immediate action would have further risked the lives of the other children. The Rainbow team manages to eliminate all of the terrorists without further loss of innocent life. The team extracts a little revenge on the terrorist who had killed the sick girl when Homer Johnston "slapped the trigger a bit hard" and the shot struck the terrorist six inches below the sternum. While killing the terrorist, the shot did so slowly and painfully. The sniper is later warned about the intentional 'miss', but no further action is taken.
By this time, Clark and the rest of the intelligence community become suspicious for several reasons: First, the surprising pace of terrorist activities; and secondly, the terrorists involved in each incident were primarily older, inactive terrorists who had not been seen in years. Thirdly, Clark's name and that of Rainbow is being brought up by people who should not be in the know. He had spent almost all of his professional life in the shadows and is very uncomfortable with the idea that he is becoming high profile.
The cause of the sudden outbreak of terrorism is radical eco-terrorists, who are owners and employees of Horizon Corporation, a large and successful biotechnology firm. They engineer a modified version of the Ebola virus, nicknamed "Shiva"; they also engineer two vaccines: a phony "A" vaccine to covertly spread the Shiva virus; and an effective "B" vaccine to protect themselves. Horizon's CEO, John Brightling, hired an ex-KGB officer, Dimitriy Popov, to foment the terrorist incidents, which Rainbow has so adroitly handled. This would increase awareness of terrorism and allow their people to get a security contract for the Olympic Games in Sydney, Australia.
Their plan is to place the Shiva virus in the air conditioning system at the stadium, spreading the virus across the world when the infected attendees and athletes, representing every country in the world, return home. Horizon would distribute further quantities of the virus, disguised as a vaccine, to every country in the world, killing everyone but the selected few. After living in sealed redoubts in Kansas and the Amazon and protected by the secret "B" vaccine, they will come out to rebuild the world in an environmentally friendly way.
Popov contracts members of the PIRA to ambush Rainbow on their home territory at Hereford, to remove them from the equation as a possible threat to Horizon's impending Australian attack. The PIRA takes several hostages in a hospital — including Patsy Clark Chavez (Ding's pregnant wife), M.D., and Sandy Clark, R.N. — and ambushes Team One, wounding and killing some of the team members. Rainbow responds by jamming the terrorist's communications and deploying Team Two to clear the hospital of the remaining gunmen. The PIRA attack is successful in crippling Rainbow Team One, leaving the way open for the deployment of the Shiva virus at the Sydney Olympics, but Rainbow manages to capture some of the terrorists alive, including the leader, Sean Grady, who is hurried off to a military hospital with gunshot wounds. They use his disorientation while he is coming to from anaesthesia after the surgery, to obtain information about Popov's involvement in instigating the attack, as well as the number of a bank account that holds the six million dollars that were supposed to be the payment for PIRA's services, along with a large quantity of medical-pure cocaine.
Popov, who had been watching the event from afar, manages to call the bank and transfer the funds to his own account, before catching a plane back to the US. After debarking at New York, he carelessly throws his passport (representing a "burned" identity) in the garbage, which is later retrieved by a waste disposal worker, and ultimately finds its way to the FBI, who start an operation to find the Russian, after being informed by Clark of his involvement in international terrorism and drug trafficking.
Bill Henriksen, a close associate of Brightling, and ex-FBI agent finds out through his contacts about the FBI's effort to find Popov. Fearing that Popov's capture by the authorities might interfere with the Project, the name Horizon uses to refer to the planned mass genocide, Hendriksen sends Popov off to the eco-terrorists' Kansas stronghold. He can't have him killed, as the ex-KGB officer might have left written instructions that, in the event of his death, might incriminate Brightling and himself before the Project can be set in motion.
By that time Popov already has some idea of his employer's motivations for inciting and financing the terrorist operations but is still unaware of the Project's ultimate goal, as he's been mostly operating on a "need-to-know" basis. Foster Hunnicutt, a survivalist in the movement, informs him of the plans just before the end of the Sydney Olympics. Popov has a crisis of conscience, and he kills Foster, then flees to New York, and contacts John Clark directly. Fortunately, Ding Chavez and a few members of Rainbow are at the Sydney Olympics as security consultants and manage to stop the person who was to infect the stadium's cooling system.
Having failed to destroy civilization with their plague, the eco-terrorists retreat to their secondary refuge in the Brazilian rainforest, hoping to negotiate a deal to return to the U.S. in a few years. Clark knows they may never even be put on trial as the destruction of the evidence is easily done - only computer records and virus samples to destroy. Clark decides to pursue them to their rainforest refuge with Rainbow under his direct leadership.
Rainbow destroys the terrorists' numerically superior but much less competent militia force, blows up the facility and communications equipment. Clark orders the survivors to remove all of their clothes and walk into the forest without any of civilization's aids, then leaves them behind, telling them that if they want to commune with nature so much, they should go commune. As Chavez wryly points out, even he himself - with all his equipment and training (Ranger School, among others) - would have a tough time surviving in such an environment.
As an epilogue, the Horizon Corporation suffered a major blow with the mysterious disappearance of its chairman but was rebounding with a new drug to combat heart attacks. Popov is living on a ranch in Montana, which he bought from the late Foster's estate. Just before Popov killed Foster, he told Popov that he'd discovered gold on his Montana property but it hadn't meant anything to him in view of the future he was embarking on. Satellite overheads show the Brazil complex to be overtaken by jungle, which doesn't distinguish between friends and enemies.