Time's Eye is a 2003 science fiction novel co-written by Arthur C. Clarke (author of 2001: A Space Odyssey) and Stephen Baxter. It is the first book in "A Time Odyssey" series. The next book in the series is Sunstorm.
The book begins as two hominids, Seeker, a mother, and her female infant, Grasper, who are somewhere in the genetic chain between humans and apes (never clearly stated, but probably Australopithecus), are examining a strange, metallic, floating orb. Suddenly, Seeker and her baby are captured by two British scouts.
The scouts return to their fort, which turns out to be housing a garrison of nineteenth-century British troops from Northern India, part of the British Empire. Another orb floats by the fort, and as the troops examine it, a ball of metal crashes near-by. The soldiers rush out to investigate.
Private Batson is one of the British soldiers at the scene and along with a few soldiers rescue the helicopter's pilot - Casey - out of the wreckage. Casey’s legs are crushed in the crash. The helicopter's two other occupants - Bisesa Dutt and Abdikadir - are relatively uninjured and all three survivors are escorted to the fort to meet the commander, Grove.
Bisesa and Abdikadir explain to Grove what happened to them. After talking for several hours both party realize and accept the fact that they, and the man-apes, are from different periods. Both parties lost external signals several hours before the crash and they hypothesized that that must have been when the “time-slip” happened. At the fort Bisesa becomes friends with British reporters Josh and Ruddy. Josh is infatuated with Bisesa and Bisesa is ecstatic at being able to meet the famous Rudyard Kipling, a man who would make considerable changes later.
As these events unfold, Musa and Kolya, two Russian cosmonauts, and Sable, a North American astronaut, are having trouble returning to Earth. They were about to return to Earth when they lost contact with ground control and the city lights on Earth went out. They manage to establish contact with Abdikadir via equipment scavenged from the crashed helicopter, and transmit photographs of the Earth. Abdikadir suggests the Earth is now made of a conglomerate of different time periods from two million years ago, up to 2037. After learning this and realizing most of human civilization is gone, the cosmonauts decide to reenter Earth’s atmosphere unaided. They decide to land near some camp fires spotted in central Asia in the hope the humans there will help them.
Upon exiting the craft Musa is decapitated by a Mongolian warrior, while Sable and Kolya are loaded onto a cart heading east. They have arrived in Central Asia when the Mongols were at the height of their power. The Cosmonauts are taken to Genghis Khan, who keeps them alive as he believes they have been sent from heaven. Yeh-lu - Khan's adviser - and Kolya work together to plan what they should do with the Mongol army. They decide that Khan should lead his army into China to rebuild the trading posts and towns that were lost in the time slip. However, Sable disagrees and convinces Khan to take the army to Babylon as this is the only place on Earth (other than Abdikadir’s radio) that is broadcasting radio signal. Sable believes this is where the power of this new world lies.
Meanwhile, in Northern India Bisesa encounters the army of Alexander the Great. Together Bisesa, Batson, Josh, and Ruddy are able to convince him to encamp at the British fort. Here the British and the Macedonians form an alliance and look toward Babylon. Alexander intends to establish a new capital there. Like Sable, Bisesa wants to examine the source of the radio signal.
Alexander’s army arrives at Babylon before Khan and has time to explore. They discover the western side of the city has been destroyed by an unknown disaster while the eastern side is filled with temples and ziggurats. A large orb - larger than those previously seen - is discovered in The Temple of Marduk and is found to be the source of the radio signals.
Casey receives a radio transmission from Kolya warning him that the Mongolians are heading to Babylon. Casey immediately informs Alexander who prepares his army for the battle. Sable catches Kolya's treachery, and Khan punishes him by pouring molten silver into his eyes and ears. Kolya is then buried beneath Khan's throne and left to slowly die.
In battle the Mongols are slaughtered by Alexander’s force, which has been supplied with firearms by British forces. At the point of the Mongolian retreat, Sable rides into the city with a hundred Mongols, heading toward The Temple of Marduk. Ruddy attempts to stop her and is shot dead. Bisesa then confronts Sable and manages to turn the gun on her.
As the Mongolian army begins another attack the British expend their ammunition. As the tide shifts toward the Mongols, Kolya detonates explosive bolts he'd scavenged from their spacecraft. Khan is on his throne and is killed in the explosion. Following the death of a Mongolian ruler, all Mongols must return to witness the heir take the throne. The Mongolian army is recalled.
Alexander has prevailed, and Babylon is now his to shape as he sees fit. The Macedonian, British, and modern humans spend the next five years rebuilding the city, while Bisesa devotes her time to studying the Marduk orb. Casey and Abdikadir are worried for her and lead her on an expedition exploring the Mediterranean Sea. Upon returning to Babylon Bisesa reveals that the Marduk orb has agreed to take her home to her own time. Josh requests she take him along and with much hesitation she agrees. They leave in the morning but the orb takes them to a large nuclear blast crater. Another orb arrives and takes her back to her apartment where her daughter is waiting for her. The orb intended to leave Josh in the crater but, at Bisesa's request, it returned him to the Marduk orb.