“… as for the idea of putting our tails between our legs and running,” he took a breath. “Tell that to the massive fucking telepathic spiders that are waiting for results!”

DB Rook is an inventive author who in his debut fantasy novel, Callus & Crow, demonstrated he wasn’t afraid to work across multiple genres and he knew how to tell a really good story. I was expecting a follow up to Callus & Crow but in his latest release, Residuum, (which doesn’t look like it should be a real word but apparently it is!) he goes off in a different direction. Residuum is an introductory novella set in Rook’s Darkening Dawn sci-fi universe. After reading this I now want to see both his projects progress as soon as possible!

Residuum opens in dramatic fashion, with teenager Charlus and her mother Merrian desperately trying to survive as strangers on a distant planet that has just been attacked by a plague of robots, known as Black Bots. Intent on destroying unworthy elements of the human race, the bots judge people by their karma, recorded on a chip everyone carries in their body. If a person’s thoughts are pure the bots will not harm them, ignoring them even whilst they calmly kill others nearby.

It’s a dire situation and after this opening things get much worse for Charlus and Merrian.

Written in Rook’s trademark episodic and action-packed style, Residuum is a gripping tale from start to finish. The use of the implacable Black Bots, who cannot be reasoned with, leads to some tense scenes, where a single stray thought by an otherwise good person is enough to condemn them. The novella reads like an allegory about the unchecked growth of things like AI and technology, where humanity’s creation ultimately defies the will of its master, with terrible consequences.

To balance what would otherwise have been a relentlessly dark story, Rook introduces a mismatched crew of space pirates led by Captain Diaz (quoted at the start of this review). I loved these characters and the sense of found family between them, which gives this book its heart and soul. Every member of Diaz’s crew is distinctive and carefully drawn, despite the short length of the book. Rook does a great job here of making you care about the fate of each and every one of them.

The Darkening Dawn sci-fi universe in which this story is set is both intriguing and expansive. Rook resolves things nicely in Residuum but also leaves a number of key questions unanswered. Residuum therefore sets things up for what I hope will be more full-length books in this world involving these characters. I think the concept is great and has huge potential, so pick up a copy of Residuum today and then DB Rook will have no excuse not to finish what he’s started. Highly recommended!

I received an advance reader copy of this book. This did not influence my review and my views and opinions are my own.