Underlings: The Spark Engine | Book Review

By Murray Fisher (pub. Toller Press, September 2025)

This was no way to die.

She closed her eyes, steadying each shallow breath, her heartbeat squelching in her ears.

Think, Evin. Think!

Deep in the city’s bedrock, face down, sandwiched in a collapsed section of tunnel, there was nobody to help her. If she couldn’t save herself right now, she may as well give up.

13-year-old Evin is a street sleeper, a spark miner down in the Bellows in the city of Lode. Then one day she finds something in the rock – a key, and a note that bears a familiar name, clutched in a skeletal hand. What could it possibly mean?

With her mining access rights revoked due to an accident, Evin now faces the daunting task of finding a new job before she gets “repurposed”. But maybe this also presents an opportunity? Alongside her new friend Kodi, and her faithful mech-dog Jet, can she follow the clues and find out the truth about Lode?

Underlings: The Spark Engine is a sci-fi dystopian story set in the underground city of Lode. The city was designed to protect people from a global disaster that hit the Earth years ago, and is divided into levels, each tier getting closer to the surface; the only way up is to work for enough credits to buy entry.

At the bottom are the Bellows, the mines where Evin and others work. Above that is the Midden, where most of the people live, subject to regular toxic air releases from the machines. Above that lies the Mezz, where many of the trades operate, though even that shows signs of neglect. Finally at the top is the Spitze, home to the elite gilders and the only level to see the sun.

This is illustrated – literally – in the front of the book with a cross-section of the city. It’s not a map exactly, as you couldn’t use it for navigation, but it definitely gives you the vibe of what it’s like!

Whatever its original intentions, the city now boasts identity numbers and barcodes on the skin, an emotionless robot security force led by the violent Vol Zygo, controlled communications, and horrible conditions for the underlings at the bottom, all under the watchful eye of Cardinal Mavka. On top of that, the tremors that shake the entire city are getting worse.

Before the story begins, we are given a brief note about the background. It’s set a long time ago, in a place long since lost under the sea, on the “far side of the world from where you are now”. This is a nice touch, as it’s an easy way for all readers to imagine it, rather than having it in a specific locale.

The story immediately shows us the danger of the world and the complete lack of care for the workers when we meet Evin, who is currently being crushed by a rockfall in the mines (seriously, the quote at the start of the review? That’s literally the start of chapter 1!)

It’s due to this that her mining rights are revoked: a faceless safetybot scans her and declares her unfit to work despite her protests, not caring that she has no other options. Evin is a survivor though and, although she’s upset, she knows she has no time to dwell on it. The city of Lode gives you no time to rest.

She has a mysterious key, and a mysterious note. It means something, something hidden about the city itself. Then she meets Kodi, who lives in a resi-hut with his uncle and aunt. Initially she intends to use them for food and shelter, but it turns out that they’re nice and genuinely want to help her. The mystery sends them all around the city, putting them dangerously in the sights of Vol Zygo.

I really liked Evin’s character; she has been raised to be self-sufficient, but there’s only so much you can do in Lode. She’s strong and impatient at times, and quick to anger when it comes to injustice which, though admirable, is not always wise! She does what she must to survive, and it’s great to watch her growth from there.

Although she is defiant, she is also only a child, so of course feels desperation and loneliness. There’s a point not too far in when she actually feels safe for the first time in a long time, and she sobs in the shower – I think we’ve all been there, just overwhelmed by all the pain and stress that when it stops, even for a moment, we simply break down.

Kodi is a bit naïve, but not entitled; he’s lived a comfortable, though not rich, life and doesn’t really know what it’s like for someone like Evin. He’s not a bad kid, but it makes a lot of sense when he wavers between doing the right thing and not causing a fuss.

Evin and Kodi get on well but are not best friends immediately, which is good. Evin is a loner who is not used to friendship, so it takes her time to open up. Some stories work well when the main characters immediately connect but it would feel weird here, especially given Evin’s trust issues and secrets.

Then of course there’s Jet. I mean, what to say about a fantastic mech-dog? I loved that he was big, and the real doggy-like traits that had been programmed into him. He’s not just a pet, he’s another character who has his own personality and sometimes makes his own decisions, whether Evin wants him to or not! He’s definitely the goodest boy.

The world and the people in it can feel like a tough read at times. Not because it’s badly done – no, absolutely the opposite. The people of Lode are unhappy and complain, but they ultimately do nothing. Apart from a few, they either accept their lot in life, or are focused inward, trying to survive or work their way up. We may not be in such dire straits, but that reaction feels sadly true to life.

The world-building is very well done, from the descriptions of the different city levels to the downtrodden-ness of its inhabitants. It’s the kind of dystopia you can appreciate as, although the setting is strange, it still feels believable, and I think a lot of it comes down to the humanity of the characters.

There’s a short glossary at the back containing words specific to Lode; I liked their unusualness, but also appreciated that none of them were so weird that you couldn’t get them from context. There’s also some discussion/writing topics and creative project ideas. I love when authors include these, as it makes it so much easier for parents and teachers to discuss the themes and ideas of a story.

(Though asking children what they think life would be like without computers and phones? Now I feel old!)

Yes it’s a great adventure book, with exciting action, relatable characters, and a mysterious quest with unexpected twists. But Underlings: The Spark Engine is also more than that – it’s also a book with a message, a message that is woven throughout the story and that permeates every level (a-ha!) of it.

It’s a message about caring for each other and for the society around us. When they discover that things are worse than they seem and that it could hurt a lot of people, it would have been easy for Evin and Kodi to ignore it, to just keep on with their lives. But they step up and do the right thing: not just for themselves, but for all the people of Lode.

If readers enjoy the story for the excitement and the imagination, then I think that’s wonderful. But if they take away even part of that message as well, then I think that’s a pretty good thing too.

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If you want to explore Lode with Evin, Kodi and Jet, you can grab a copy of Underlings: The Spark Engine at Waterstones here.

Looking for more dystopian reads? Check out some of our previous reviews here!