The novel begins with a recollection of a young girl called Rose falling into a pit on her family farm. After rescuers come, it is discovered that the girl has fallen into a giant metallic hand. Now an adult, Rose is a scientist, and she is interviewed by an unnamed character about the even from her childhood and her decision to pursue the meaning behind the giant hand. This unnamed interviewer is also a person of great wealth, and he reveals that he is willing to fund Rose’s research of the hand and the discovery of other parts.
Rose Franklin discovered that a compound called argon-37 is what triggers the appearance of body parts of the giant metallic robot after an accident that took place in Turkey and led to the appearance of the robot’s forearm. The pilot of the plane that was involved in the accident is a woman called Kara Resnik, and she, alongside her co-pilot, gets recruited for the mission of the body parts’ retrieval. To decipher the codes on the body parts, a young linguistic student called Vincent gets recruited as well.
The retrieval of the body parts leads to political and international crisis because of the US’s exploration of foreign grounds. As the robot is being slowly assembled, Kara and her co-pilot are practicing the control of it in the chamber inside its torso. The head part of the robot reacted and accepted Kara as the host, while the leg-part didn’t accept Ryan. Vincent, the linguist, tries the leg-part helmet on, and it reacts and accepts him as the host, which is devastating to Kara’s co-pilot, who is also in love with Kara.
As Kara and Vincent grow closer, Ryan’s jealousy leads him to hit Vincent with a truck, completely destroying his legs. Before Vincent’s legs get amputated, the unnamed leader of the project forces a doctor to operate and save his legs with titanium material. One important aspect of the leg-part of the robot is that the knees are inverted, so Vincent’s operation includes the addition of this aspect to his new legs.
After the entire robot gets assembled, Kara and Vincent decide to try out what they’ve been practicing. This leads to a tragic accident at the compound, death of Rose Franklin and destruction of Denver airport. The secret of the robot is revealed to the world and the unnamed leader is forced to get rid of it to prevent a war crisis.
Some time passes, and the unnamed leader assembles the crew once again, and they work on rebuilding the robot in Puerto Rico with a new overseer of the project, a sociopathic scientist called Alyssa. They reveal the robot to the world, and it becomes property of all the great nations. In the meantime, the unnamed leader of the project has a conversation with another anonymous individual, and they talk about where the project came from, how it was left behind by a great alien nation that inhabited the Earth three thousand years ago as a test of humanity’s evolution.
Alyssa, the new leader of the project, attacks the coast of Korea with the robot despite the unnamed leader’s directions against that. This leads to a new crisis, the robot and the crew are threatened by the US government for treason. Alyssa also leads vile experiments on Vincent and Kara to discover why only they can control the robot. She also recruits Ryan, who, after becoming aware of the extent of the experiments, decides to help Vincent and Kara escape the compound in Puerto Rico.
Meanwhile, the compound is approached by the US military to imprison the people there. Alyssa manages to escape without a trace. It is revealed that she is actually of Bosnian heritage, and not from Greece, and that she led gruesome experiments during the war in Bosnia. The unnamed leader manages to convince a US government official to no longer held them prisoner and that what he did was to protect the US. The novel ends with the reappearance of Rose Franklin in Denmark, with no memory and five years younger than she was when she presumably died.
