Intrusion: 1995 lasts one page and sets the scene for the world the reader is about to inhabit. It describes a force invading a sleeping woman's pregnant belly without hurting or waking her. It lies dormant there in her child for years, and the woman dreams of an owl. Later, one day, she sees an owl like the one from her dream in the zoo. It unnerves her. The chapter ends with the observation that the woman is not the first to dream about the owl, nor will she be the last.
The Last Historian begins with Cassie, our protagonist, musing on the difference between what humans imagined aliens to be, and what they actually are. The Others are very smart and eons ahead of humans in technology. They arrived just a few months ago and turned the human world upside down. Cassie is wandering through the countryside alone, trying to survive, yet desperately afraid that she may be the last human alive. She hasn't seen anyone else for weeks.
While foraging in a gas station for food, Cassie runs into another human. She is wary of him, worried that he may be simply an Other posing as a human. He is gravely wounded and holding his hand to his stomach. Cassie orders him to show her his hand but when he does, she sees a flash of metal. Fearing the worst, Cassie shoots, only to discover that the soldier was holding a metal crucifix.
That was the last person Cassie sees for a while. She packs up her tent and supplies and goes on the move again. Cassie remembers how people reacted when they found out the Others had arrived. The Majewskis, for example, decided to go to Disney World and enjoy their last days. Cassie's world continued in a rather boring and predictable way at first, with a curfew imposed and her going on a date with a boring boy named Mitchell in her backyard. Everyone assumed that somewhere, someone was in charge and the government would coordinate at some point.
She explains that there are were four waves of attacks from the Others. One was an electromagnetic pulse that wiped out the cars, radios, everything. The second wave was tsunamis that decimated the coastline, the third was a red plague called the Pestilence, and the fourth was the Silencers, Others, and drones who went around killing the humans they encountered. Cassie comes across three of their bodies, still warm, when she nears Cincinnati. People suspect that there is a fifth wave coming, but so far they can't figure out what it will look like.
After the third wave, Cassie's Dad took her and Sammy to a refugee camp where they should have been safe. However, soldiers came and took the children away on school buses to the army base at Wright-Patterson. After the children, including her brother Sammy, were gone, all pretenses were dropped and the adults left were slaughtered by a sound wave. Cassie barely escaped thanks to her father, who sent her out to get Crisco. The soldier with her killed Crisco, but Cassie killed him in turn.
She took off running and hid in the ash pit of the bones of people who died from the red plague. The soldier walked right by her, not looking under the bones. She was also hit by the 200-decibel sound wave, but she was far enough away to be relatively unscathed. She took off running into the woods with little but her rifle, a Luger, and a teddy bear.
Back in the present day, the Silencer who killed the three people Cassie found is now hunting her. He has managed to shoot her in the leg, but Cassie has hid under a car, a Buick. She tries to figure out how to get away.
Cassie details how she survives in a world alone. She tries to avoid drones by traveling at dusk, the time when they are least prevalent. She also explains how the Hum, the noise of all electronics, is gone. She describes how the Others were systematically knocking humans back into the eighteenth century, then back into the Stone Age, making them utterly helpless against the Others.
The second wave, the tsunamis on the coast, along with the red plague of the third wave, are the two most destructive of the waves. Altogether, the waves have wiped out 98 percent of the human population, or about 7 billion people. The third wave was the longest, lasting about three weeks. Cassie's mother died as a result of the third wave.
Soon after Sammy boarded the bus, Cassie and her Dad have a bad feeling about the situation. Her father makes the ultimate sacrifice to make sure she has a chance at getting out alive. Cassie also makes a promise to Sammy that she will come back for him. She takes the teddy bear he offers and it becomes a symbol of their bond. It also foreshadows that she will one day make it back to Sammy to give it to him, or die trying.
From the beginning, the soldiers at the camp act suspiciously, foreshadowing their duplicitous nature when they ask the adults to surrender their weapons. Cassie realizes that her father hid the M16 rifle that he showed her earlier in a tree. This rifle saves her life many times over the course of the book and gives Cassie power over enemies much larger than she.
Cassie ends the chapter alone and afraid, much like she started out the chapter. Not much has changed in her life in the time since her father died and her brother was taken away. Cassie is kept alive by the hope that she can save her brother and that she is not alone. At the same time, she is plagued by the fear that she is alone. She is revealed to be a complex and well-drawn character, who draws the reader in with her sarcasm and empathy.