Throwback follows Corey as he learns that he can travel back in time. This isn't unique - others, like his grandfather, can do it, too, but Corey is a rare individual who can change past events. After learning this, he decides to go back to 2001 to save his grandmother, who died in 9/11. However, he ends up 1917, loses the items required for his return, and is left to fend for himself.
Full disclosure: I read the first half of the sequel, Chaos Loop, by accident before reading this book. Thus far the sequel is much stronger than this book, so if you enjoyed/were on the fence for this one, give the sequel a try!
I could not connect with Corey as a main character. The story tells us a few quirks about him like he's 'a throwback to a more civilized age' or nerdy, but honestly, I never got that from his dialogue or actions. He reacts to time traveling the same way every time it happens and doesn't process the events of the story. The main motivation, saving his grandmother, is absent much of the story and Corey doesn't seem distressed either by the possibility of being trapped in 1917 or worried that he'll massively change the future by accident.
SPOILERS TO FOLLOW
The plot was a lot of filler. The goal of the 1917 bit is for Corey to get back to the present, but surprisingly little time is spent on this. Instead, it's around him bonding with a cowboy and learning to ride a horse. Given the setup, I expected more urgency in the plot.
There is also a subplot with his friend, Leila, that amounts to nothing and has no impact on any of the events of the story aside from establishing a few things that will be relevant in the sequel. The grandfather mentions that people will want to exploit Corey's ability to change the future, but nothing comes of this either.
Lastly, there is a character in the story who is a girl pretending to be a guy, and it just confused me. Corey's reaction made it seem like this character was a commentary on being transgender in the past, but I don't think the character is transgender because the story refers to her as 'she' for the rest of the book. The way she talks about her reasons for pretending is much more in line with that she's a girl who just wants to be a cowboy, which is more commentary on gender roles. Either way, the story just frames this in a manner that's very confusing.
On the positive side, the story reads fast and, despite the fact that nothing was happening, it did keep my interest. If I hadn't read half of the sequel by accident already, I probably wouldn't pick it up though. The sequel seems to be much better so I'll finish it up.