CIA Special Agent Jenny Hunt, an attaché at the US embassy in London, travels to the west coast of Scotland to confront former Royal Marine and Special Forces officer, Jamie Shaw.
There, she finds him living an apparent quiet life on the Isle of Skye.
Over after-dinner drinks Hunt lets it be known that she has intelligence that links Shaw to the revenge killings of several Israeli cocaine traffickers; members of a cartel responsible for the murders of his wife and daughter, whilst he and his family were living in Oman, employed by the late incumbent Sultan of Oman, as military adviser to his special forces.
Hunt points out that as his revenge spree included a murder in Los Angeles, he is wanted by US authorities.
Hunt calls in the debt: the abduction of Prince Richard, a nephew of the Queen, and wanted in the USA by the FBI on paedophilia charges.
Left with no choice, Shaw arranges the snatching of the prince whilst he is fishing on the Balmoral estate, Royal Deeside. A waiting US submarine submerged off the coast of Scotland, transports the reluctant royal, stateside.
Shaw resumes his life only to again be visited by Hunt. This time it's a personal request. Aware that Shaw can deliver the goods, Hunt and her sister, an anthropologist and with a book and movie deal waiting in the wings, offer Shaw a lucrative mission. Visit North Sentinel Island and obtain evidence as to the islanders - a pre-neolithic tribe who have inhabited the island for approximately sixty five thousand years - way of life.
Initially, Shaw is reluctant. He discovers it's illegal to visit the island and that the inhabitants are dangerous, as the killing of US missionary, John Chau, in 2018 is testimony.
However, after negotiating a larger reward, Shaw accepts the challenge and undertakes a HAHO parachute jump in order to get on the island covertly.
There, he sets camera-traps and probes deeper into the jungle. Before long Shaw discovers washed-up parts of a airliner that the Sentinelese have gathered. Further investigation reveals the aircraft parts belong to missing Malaysian flight MH370, last seen heading towards the Andaman Islands. Shaw pushes on further and discovers enslaved survivors of the flight - and the remains of others used for sacrificial slaughter. Shaw photographs as many of the passengers as he can.
After recovery from the island, he surrenders the evidence.
During debrief, Shaw reveals all.
His plea for authorities to rescue the survivors falls on deaf ears. Furthermore, he is threatened as to his participation in the kidnapping of Prince Richard, should he divulge what he witnessed on the island.
Reunited with Hunt, Shaw learns US intelligence is behind the downing of the airliner. Furthermore, they have known for many months that survivors from the flight made their way to the island. However, only one possible survivor, a Chinese virologist from Wuhan, is of interest to the CIA. As he wasn't amongst those still alive - case closed.
Though Hunt denies it, Shaw realises he has been duped.
Despite the threats, Shaw sells his photos and story. He's dying of cancer and is untouchable. The RSPB are going to receive a windfall, though.