An American squad deployed in Afghanistan is unexpectedly transported into the Stone Age. The ten soldiers now have to somehow survive in this past era, having nothing but two armored cars and the gear inside. To complicate matters, other groups from across time have also been transported here, including a Neolithic tribe, a Roman legion and two men from the future, and not all of them are friendly... Can the Americans survive? Will they ever get back to their time?
To a large degree, the novel is written as a robinsonade; a lot of space is devoted to lovingly detailed descriptions of how the characters manage to survive and settle down in the Stone Age era. As a result, the plot itself moves at a rather relaxed pace.
The novels contains the following tropes:
- Covers Always Lie: The cover shows an American GI, a Roman legionnaire and a stone-age spearman riding in an armored car while being attacked by mammoths and a woolly rhino. This doesn't happen in the novel; instead there's a chapter where Americans, Romans and prehistoric men go hunt rhinos on foot, and another separate scene where a Roman gleefully rides on top of an armored car.
- Cunning Linguist: Oglesby, indispensable to maintaining a rough communication between the American and the more primitive people.
- Dramatis Personae: The end of the novel has a list of all named characters, including those who only appear once or twice.
- Genre Savvy: The soldiers have read enough sci-fi that, upon being transported through time, they don't need much time to figure out what has happened. It doesn't make them any less traumatized and horrified, however.
- Language Barrier: The Americans have obvious difficulties in communication with the Stone Age people, the Neolithic tribe, and the Roman legionaries, although in the latter case they can sort-of make do with words that have Latin roots.
- A Little Something We Call "Rock and Roll": The Americans participate in a dance festival at a Stone Age village, and play some techno music (including Skrillex), which the Stone Agers find confusing at first but really enjoy dancing to.
- Living Prop: The Roman camp includes a handful of time-shifted conscripts from India. In contrast to the other groups, the Indians never get any focus and aren't given any personalities or names.
- The Medic: Devereaux, who not only cares for the troops' well-being, but helps them earn the Stone Age tribe's friendship by offering medical care to the villagers.
- Never Trust a Trailer: The official blurb says that the two time-travelers from the future "may have the means to get back, but they aren't giving it up. In fact, they may have a treacherous agenda of their own, one that may very well lead to the death of the displaced in a harsh and dangerous era." In actuality, the time travelers from the future are happy to help the heroes return as soon as the means presents itself, and there's barely any "treacherous agenda" involved, apart from a short scene where the scientists of the future world ponder if they should indeed return the Americans to their time.
- Outgrown Such Silly Superstitions: It's mentioned that religions still exist in the future era, but pretty much all adherents treat their holy texts as symbolic or metaphorical, and don't truly believe in the supernatural.
- Porn Stash: At one point, Gina gathers everyone's electronic devices to pool their software and data. In the process she ends up catching glimpses of the male troopers' porn collections, much to their chagrin.
- Robinsonade: The characters are stranded in a wild environment and have to make do with whatever they can build on their own.
- Shown Their Work: The author put a lot of work into researching Stone Age-level technology and survival techniques, even writing a short article on what the research entailed.
- Sudden Lack of Signal: After being mysteriously transported, the soldiers quickly realize that they cannot reach anyone on the radio and the GPS isn't working either.
- This Is My Boomstick: Used as a humorous inversion. The Roman legionaries attempt to intimidate a squad of modern-day American soldiers by demonstrating 17th century muskets. The Americans quickly put them in their place by showing what their guns are capable of.
- Trapped in the Past: The plot revolves around the ten American soldiers (and other groups) ending up trapped in the Paleolithic era.
- Two Girls to a Team: There are exactly two girls in the American camp. This is Played for Drama, since (other than the Stone Age women) they are the only girls around, and so they feel they are in constant danger of rape.