The common thread through this whole action-packed sci-fi novel, Zero World by Jason Hough is, in a word, mystery.

Peter Caswell is an assassin who works for a mysterious organization. But he’s no ordinary assassin, because his memory of the mission gets wiped every time, leaving him with no memory – or guilt – of those who he killed. Who did he kill, and why? He doesn’t know – and he doesn’t want to know.

The book begins when his employer assigns him to investigate a spaceship that mysteriously disappeared and has since re-appeared. Its entire crew – save one person – mysteriously turns up dead. And that one person? Missing, of course.

I won’t give away any more of the plot, suffice it to say that it’s a page turner because author Jason Hough is adept at leaving a trail of questions for the reader. As soon as something is revealed, another mystery pops up in its place.

The writing is excellent – it’s simple and straightforward. The characters are fleshed out, and the action scenes are thrilling without becoming sodden from too many details that so many authors love to inject in them. If you start reading this book, make sure you have a few hours to kill, because it’s awfully hard to put down.

Thematically, it explores self-identity. Peter doesn’t want to remember anything about his past life, and another character has to wear a mask in order to survive, and a third character projects to be someone she is not. In each case, they’re forced to confront their own sense of self and their preconceived notions on how things ought to be. Since who they want to be and who they actually are come into conflict, it helps drive the plot. Hough gives us just enough of this element to make his characters feel developed and three-dimensional, but not so much that it drags down the story.

Disclaimer: I won a free copy of this book via giveaway. If I didn’t like the book, or thought it was just all right, I wouldn’t be leaving this review. This book is legit, y’all.