The following version of the book was used to create this study guide: Brown, Erik J. All That's Left in the World. HarperCollins Publishers, New York, NY, 10007. 2022. AZW file.

A pandemic has wiped out more than 99 percent of America's population. Andrew cannot help but imagine the pre-pandemic survivalist who set the bear trap that Andrew stepped in a couple of days ago. His leg is terribly mangled, and Andrew needs to find first aid supplies to address the wound. He stumbles upon a cabin, climbs the steps, and finds the front door unlocked. Inside, Jamie is taking stock of the food he has left. He is quite comfortable in this cabin which has solar power and is well stocked. He grabs a gun and orders Andrew out. Andrew's injury is so severe that he simply refuses to leave, and Jamie uses the information his mother left him to clean and stitch the wound. Knowing that Andrew's leg might actually be broken, Jamie allows him to stay. A few weeks later, they have settled into a comfortable life when some people from a nearby settlement arrive. They demand payment of “taxes” and take a lot of Jamie's food. Jamie realizes he is going to have to get over his reluctance to hunt and sets out the next morning. He cannot bring himself to kill the deer he sees despite his concern about food. At home, he discovers Andrew has left.

Jamie feels sure Andrew is headed to Alexandria, Virginia, having seen a paper with a name and address the first day of Andrew's arrival. Jamie catches up with Andrew who is relieved to have the company. Andrew does not reveal that he is going to Alexandria to tell a man named Marc Foster that he killed Marc's parents. He does say that he has heard rumors of foreign aid arriving in Washington DC in early June. As they travel, they meet with a kind woman named Henri who tells them about her daughter who lived in Florida before the pandemic. They discover that Marc Foster, his wife, and their two daughters are dead, and they take time to bury the family together. At the airport, the find a young man who has official government document confirming that other countries did not fare any better than America, and that there is no one left to offer aid. They set out for Florida in the hope of finding Henri's daughter.

On the way, they find a large settlement called Fort Caroline. Though there are some positives, Andrew and Jamie immediately agree they cannot stay here. The son of a town official seems to know Andrew is gay. A few days after leaving Fort Caroline, Harvey Rosewood confronts Andrew and Jamie, and Jamie kills them. They discover that a young woman name Cara has also fled Fort Caroline, and she joins up with them on the road. By this time, Jamie has come to realize that he loves Andrew, but he worries that his feelings are prompted by the situation and are not real. Just as he works up the courage to tell Andrew, some men from Fort Caroline catch up with them. Jamie and Andrew have only a few minutes to talk and share a kiss before they are running for their lives through the woods. Jamie is shot, and Andrew and Cara carry him in a cart as they make their way south to Florida. They discover that Islamorada has become a thriving community. They treat Jamie's injury in their functional hospital. When Jamie is released, they find Henri's daughter Amy who now has a daughter named Henrietta. The people of Islamorada are protective but open, meaning Jamie and Andrew can remain here if they choose. They know there is always a potential for conflict, including fights with other settlements. They consider returning to the cabin. They know that they can survive as long as they are together.