A researcher, Steven Grant, is on the brink of a discovery of global significance. Steven needs just a few more DNA samples from remote, indigenous people in Pakistan and Australia to bring his research to a conclusion. He then receives a serious threat - if he continues his research, he will face serious consequences. This letter and further attempts on his life fuel his determination to find who is behind the threat.
Despite objections from his new girlfriend, Rachel, that it is too dangerous, he flies into Karachi to take a domestic flight to the north of Pakistan. While in Karachi, he meets a Chinese expatriate worker, Esther. Their relationship develops. His uncle, a businessman in Karachi and with whom Steven is staying, tells Steven of his illicit relationship with Steven's mother many years in the past. Before Steven can process this information, his trip is interrupted by his mother's ill health. He returns to the UK.
While back in the UK, he meets with his brother and learns that his uncle had abused his brother when he was young. Steven's property is targeted by an arsonist. He vows to return to Karachi to confront his uncle, to spend time with Esther, and to discover who is targeting him.
On his return to Pakistan, he gets the DNA samples he requires, but an unknown party steals them following an earthquake. Meanwhile, a group of northern tribesmen kidnaps Esther. The kidnappers will only speak with him to arrange the ransom. He embarks on a quest to rescue his beloved, unaware that Esther has betrayed him by bargaining with the kidnappers and that he is walking into a trap. When Steven escapes from the kidnappers, the leader of the gang shoots his travelling companion, Tahir. Steven is now on the run, desperate to retrieve the DNA samples he badly needs. He returns to the clinic in the north and finally obtains the samples.
Steven returns to the UK. He publishes his research findings in the Lancet. The article proves that a US company had allowed harmful substances to be used in plastic food packaging that damages DNA. He tries to be reconciled to Rachel, but she has started a relationship with his brother. Then unexpectantly, he meets Esther's sister, a girl he wronged in his youth.