Hal Ambler has to find out who shut him away in a mental asylum for former spies and prevent an innocent man from being murdered. Hal Ambler, a member of the clandestine Political Stabilization (Stab) unit of the Consular Operations, has no recollection of how he ended up in a maximum-security asylum for the mentally ill. With the help of a sympathetic nurse Laurel who understands that he does not have any mental problems, Hal manages to stage a daring escape.
Hal finds his way back home only to realize that his former friends are unable to recognize him. When he looks into the mirror, he finds a different face looking back at him and he is suddenly scared whether he has actually become mentally ill or delusional. He is troubled by nightmares concerning his last mission as a Stab operative when he was sent to kill a promising young Taiwanese politician. Hal has a unique skill - he is able to tell whether people are saying the truth or lying just by looking at them. Hal realizes that the Taiwanese politician is not a bad man as his superiors told him and tries to abort the mission, but it goes through and an innocent life is cut short. However much Hal tries, he is unable to remember what happened next.
When Hal overpowers a thug sent to capture him, he comes to know that a group is interested in enlisting his services. Hal, or Tarquin as he is know in the world of espionage, meets Osiris an ex-Stab operative, who tells him that he may have been brainwashed by certain people to make him forget who he really is. Osiris is killed by a Chinese man but Hal manages to escape. Hal goes to Laurel's house in hope of talking to at least one person who knows him and is struck by her love, beauty and devotion to him. She convinces him that the others are lying and he actually is Hal Ambler.
Hal meets Fenton, the leader of the Strategic Services Group which wants him to work for them and Fenton asks him to kill the chief of the IMEA. Fenton tells Hal that the IMEA chief is secretly helping enemy countries acquire nuclear capabilities. When Hal goes to Paris to kill the IMEA chief, Laurel tags along with him saying that she wants to help. Hal feels that her life may be in danger because she helped him and feels it is better if they are together. Hal and Laurel are also immensely attracted to each other.
To fool the SSG, Hal tries to stage a false assassination but someone else kills the IMEA chief and the blame is placed on Hal. A CIA officer Clay Caston who is trying to find the patient who escaped from the facility for mental patients realizes that there is something shady going on. He catches up with Hal and together they try to analyse whatever has happened. With Clay's help, Hal remembers that he had gone to his superior Ellen Whitefield to complain that his last mission to Taiwan was staged on false data, but she had ignored him. He had gone to her house one day unexpectedly to find her in deep discussion with another man. He describes that man to Clay and Clay understands that that man was Ashton Palmer - a political fanatic with strong anti-China views.
Hal and Clay realize that whatever has happened till now has indirect links to China. The Taiwanese politician who died was pro-China. The IMEA chief was working on a report which would have cleared the Asian country of nuclear proliferation efforts. The new Chinese president is attending a World Bank event in Geneva in a few days and they fear that someone may try and kill him.
Hal, Laurel and Clay find their way into the event without raising suspicion. Clay manages to corner Ellen and Palmer and gets them to confess the whole conspiracy on videotape. Hal tries to find the killer in the conference room even as the Chinese president is speaking to the audience. At the last minute, Hal realizes that Laurel has been sent to kill the Chinese leader. She had been fooling him all along and had wanted him to be at the event so that the blame would fall on him. Hal stops Laurel from killing the foreign politician and she dies in the ensuing fight.
Best part of story, including ending:
It is a gripping thriller from start to end. Hal is in a unique situation where he doesn't know whom to trust. His unique talent is that he can immediately say whether a person is lying or saying the truth, but Laurel manages to fool him till the bitter end.
Best scene in story:
At the final event in Geneva, Hal enters the auditorium where the Chinese president has to give his speech. Laurel is very helpful and manages to get her and Hal too video cameras so that they can try to pass themselves off as television reporters. At the last minute, when Hal is surveying the crowd through his camera, he catches a fleeting glimpse of cruelty and contempt on Laurel's face and he realizes that she is a liar. He is heartbroken to realize that the woman he loved had been using him all along.
Opinion about the main character:
Hal Ambler is one of the toughest operatives that the Stab has ever known. In spite of this, he has a cynical sense of humour that surfaces in his interactions with Clay. He loves Laurel with all his heart and feels responsible for putting her in this situation, not knowing that she had been manipulating him all along.