I’m a sucker for books with ominous warnings of offensiveness on the cover, and they’re usually there for a reason. But while it means that some extreme horror is on the way, it doesn’t necessarily follow that it’s any good.On this occasion, I needn’t have worried. One of Matt Shaw’s infamous “black cover” series, this joint effort with Michael Bray is a bleak yet entertaining short novel.

We meet Ryan, a young office-worker, who wakes to find himself chained up in a grimy chamber of cold concrete and rusting pipes with no idea as to how or why he got there. It turns out that just prior to this, he’d discovered his short-term girlfriend was pregnant. Rather than head home to deal with the issue, he instead went to the pub with a friend to blow off steam, and this is the last thing he remembers.

Also introduced is Christina, a young mother working in a petrol station who entertains herself during the dull shifts by making up macabre stories about the customers being psychotic serial killers. One day however, she is somewhat too close to the truth and also finds herself imprisoned in the same dilapidated building.

Kicking off with a somewhat cinematic start that put me in the mind of “Saw”, I liked the immediately engaging character situations presented by “Monster”. These are normal people in whom we can invest, and there’s a tight air of mystery along with the anticipation of nastiness that surely awaits them. Because as well as Ryan and Christina’s initially-hidden captors, the building also seems to be home to an enormous mentally-ill man loping around the filthy corridors.

The book is pacy and well crafted, filling in the back story by switching between the 1st and 3rd person. The aura of menace cranks up slowly, and both Ryan and Christina’s reactions under the mounting terror are convincing. They have moments of sheer panic followed by stoical resolve and then back again, sometimes the desperation leading them to hope that all this is just one big extreme prank. One scene in which Ryan is fed morphine to stop him passing out from pain could have been darkly amusing in a different setting, such is his garbled, comical speech, but here, it’s used to true chilling effect.

As the book progresses, we meet the faces behind all this and learn their horrible plans. Their histories are just as dark as the current scenario, and they’re anything but one-dimensional monsters. These kidnappers are broken by being the victims and/or perpetrators of genuinely upsetting physical and psychological abuse, and the book riffs on some classic questions. Who’s the monster? Is there even one? Can somebody so damaged be evil? But the answers are not black and white, and the story didn’t pan out the way I thought, playing with my sympathies all the way.

As the warning would suggest, there are some harrowing scenes. I was pleased to discover that they aren’t gratuitous – there really is nothing more boring in horror – but essential to the questions that “Monster” presents. I’ve read stories that are more extreme than this, but finished them with a shrug and a whatever. Here, the horror is gauged just right to get under your skin. It’s not just the actual violence that disturbs, but also our potential for it, and the numbing consequences of systematic, accumulative abuse. There’s no humour, and some sections of the book are both deeply touching and depressing.

Being picky, I have two small gripes. The prose is generally slick and unintrusive, but there were a couple of times when the character POV changed mid-scene without warning and took me out of the moment. There is also a scene in which one character is forced into a terrible act, and it just seemed to happen a little too easily for me. But they’re my only complaints.

The finale is appropriately painful and sobering, but there’s also a nice little epilogue that raised a smile. It’s a classic vignette with a tone of ominous fun, and the only time that this very dark novel has a wry twinkle in its eye.

So there you have it. An eloquent introduction from both Matt Shaw and Michael Bray explains the nature of extreme horror, pushing the boundaries, and the fine line such authors tread. It’s refreshing to see such thoughtful reasoning in the subgenre, and that the shocks are intended to be a means to an end and not simply the end itself.

Happily, “Monster” is just the right side of the line. It succeeds by luring your ghoulish curiosity, working in some solid character investment to stop you getting away, then drags you off to hell. The themes of survival and the nature/nurture argument are tackled intelligently without playing killjoy to the grisly shenanigans, and I liked the lack of distinction between good and evil. And it certainly gets its hooks in. I read it during a work day, and snatched every coffee break or bus journey to get back to that grim place of blood-stained concrete and death. I’ve already downloaded another of the black cover books by Matt Shaw, and I suspect it won’t be the last.