The Quarterlands brings Xanthe Walter’s compelling Dark Water series to an exciting and thoroughly satisfying close, trying up all the loose ends and resolving the intricate mysteries at the heart of the series. As this is a story spanning four books, it’s essential to have read the first three before this one, and this review will contain some spoilers for those.

The series, set in a dystopian future in which much of the world has been submerged, kicked off with a murder, which put investigator Josiah Raine and indentured servant Alex Lytton into each other’s paths. We’ve learned how Alex – a seriously messed-up kid from a privileged background – was made the target of a cleverly orchestrated vendetta by the machiavellian George Tyler, a powerful and incredibly wealthy businessman who had once been a close friend of Alex’s father, but is now his implacable enemy. And we’ve watched Josiah, a man whose heart has remained frozen in the seven years since his beloved husband was killed, slowly regaining himself and his purpose in life as, with Alex’s help, he’s learned to let go of the past and to start to move on.

By the end of Ghost Eye (book two) Alex had come to trust Josiah enough to tell him about what happened to his dearest (and only) friend, Solange – who was killed by Tyler in a fit of rage – and that finding a way to bring Tyler to justice for what he did has been his one sustaining purpose throughout the years of servitude and abuse he’s lived through. In book three, The Lost Zone, we witnessed past-Alex learning how to transform himself from an angry young man intent on preserving his identity and raging against the machine into the perfect IS, focused on service, on doing whatever will please his houder (owner) and completely subjugating his sense of self in order to present a serene and impenetrable mask to the world in order to keep his true thoughts and purpose well hidden.

The past timeline of The Quarterlands picks up shortly after where it left off in The Lost Zone, with Alex having returned to Tyler following his stint at Belvedere, and with their fucked-up relationship having resumed – and set to become even more fucked-up than it already was. Tyler is very much the villain of the piece, yet there has always been something darkly compelling about him, something Alex was attracted to back when they first met, and which has now become something dark and twisted. Alex can’t explain it or understand it – he hates Tyler but he’s drawn to him, too, and he realises that Tyler is as caught up in this twisted web of loathing and desire as he is himself. As time passes, Tyler’s warped obsession with Alex becomes all-consuming and ugly, and eventually, living on a knife edge, trying to judge Tyler’s increasingly volatile moods and being subjected to his escalating outbursts of violence take a massive toll on Alex’s mental health, and he becomes increasingly withdrawn and dissociated, losing all sense of self and purpose.

In the present day timeline, Josiah, increasingly concerned about Alex’s fragile mental state as the investigation into Solange’s murder has progressed, and realising that Alex is not in a place to have a romantic relationship with anyone, told him that they should go back to being just friends. It almost killed him to do it – he’s deeply in love with Alex – but Josiah is well aware that Alex isn’t free to be with anyone, and that what he needs now, more than anything, is support and unconditional love while he heals from the emotional and physical trauma of the past seven years. He reaches out to Noah and Charles Lytton, hoping that having the two people Alex loves most of all back in his life will help start him on the road to recovery.

While Josiah is looking out for Alex and continuing to prepare for Tyler’s trial, he’s hasn’t given up on finding out who killed celebrity holographer Elliot Dacre – the murder which originally bought him and Alex into each other’s orbits. He’s sure that Dacre’s death is somehow linked to Alex, even though he knows Alex wasn’t responsible, and ever since he learned about what happened to Solange, Josiah has felt sure that there’s something else, something big, that Alex isn’t telling him – and he can’t let it go. The things that have made him one of the finest investigators in the country – his ingrained drive to search for the truth, his instinct, and his deep-seated sense of what’s right – make it impossible for him not to keep digging into Alex’s past. As Alex continues to repair his relationships with his father and brother and to regain his health, physically and mentally, Josiah doggedly continues his investigation into Dacre’s murder – and as he finally unmasks the killer, he also works out the terrible secret Alex has worked so hard to keep hidden for over a decade.

Dacre’s murder is finally solved in this book, and I had no idea as to who the killer was beforehand. If I have a complaint about the Dacre plotline, it’s that that reveal comes just a bit out of left-field; the reasons given absolutely hold up – my issue is more that I didn’t get to see how Josiah worked it out.

All the books in this series have been tremendous, nail-biting rides on an emotional rollercoaster, and this final instalment is no different. Xanthe Walter does an amazing job here of pulling all her plotlines and timelines together to produce a cohesive, exciting and incredibly gratifying finale that puts readers through the emotional wringer alongside the characters. The two timelines align perfectly and bring us full circle to the ‘first’ meeting between Josiah and Alex, this time told from Alex’s perspective, and Alex’s big secret (I had guessed the ‘what’ but hadn’t worked out the ‘how’ and ‘why’) is finally revealed.  My heart broke over and over for him – he’s been through so much, made so many sacrifices and been so badly misjudged by almost everyone. He’s so broken yet so strong – a flawed, multi-faceted individual who goes on an incredible and sometimes brutal journey of growth and self-discovery, evolving from a confused, traumatised young man who makes some bad choices and doesn’t always treat people very well to a wiser, much more compassionate person who has come to a very hard-won deeper self-awareness and understanding of himself.

Josiah, too, has come a long way from the man moving through his life on auto-pilot we first met. He’s rejoined the land of the living and has opened himself up to the possibility of love again, he’s re-energised when it comes to his job and is determined to get to the bottom of the secrets surrounding the Lyttons. But his compulsion to seek justice at all costs finds him facing an impossible choice, one with the potential for devastating personal consequences. Does he continue his search for the truth and possibly lose Alex forever, or does he abandon it and lose himself?

The worldbuilding is, as I’ve said before, rich, detailed, and vividly imagined, and I have to applaud the author for her scarily plausible take on what happens to a society that suddenly finds itself irrevocably changed. The cast of secondary characters who appear across the series is superbly drawn and the two leads are complex, imperfect, damaged men who have managed to retain their humanity despite experiencing some horrific and life-changing events. Alex and Josiah’s journey has not been an easy one, and there have been some harsh words and deep wounds inflicted along the way, but by the time we reach the end of the story, they see one another for who they really are and are ready to move forward together.

I can’t talk about the excellence of the characterisation without mentioning the other most important character in the series, George Tyler, and how much I appreciate that he’s so much more than a one-note, moustache-twirling villain. He is a villain, no question – but he’s also charismatic and dynamic and passionate, and it’s easy to understand why younger Alex falls so easily under his spell. There are even moments – very tiny ones of course! – in this book where I almost (almost) felt sorry for him. And much as it pains me to say it, I couldn’t help thinking that the relationship between Alex and Tyler – incredibly toxic though it is – has more chemistry and development here than the romance between Alex and Josiah does. I understand the need for the focus on the Alex and Tyler dynamic, but I’d have liked to have seen a bit more of the development in Alex and Josiah’s relationship in this final instalment of their story.

Although it was sometimes difficult to see how an HEA for Alex and Josiah could be arrived at, I trusted the author when she said there would be one, and she has come up with an ending that feels absolutely right for these characters and which delivers poetic justice in the best way. Would I have liked to spend a bit more time with Alex and Josiah after I read “The End”? Yes, absolutely – it’s always hard to let go of characters you’ve become so invested in. Am I happy with where they’ve ended up? Again, yes, absolutely. Their HEA has been bloody hard-won and they deserve every damn second of it.

The Quarterlands is another fast-paced, thrilling and engrossing read, and while I’m sad to have reached the end of Alex and Josiah’s story, I enjoyed every bit of the time I spent in this world with them. Clever, compelling and utterly addictive, Dark Water will definitely be making an appearance on my Best of 2025 list, and it’s a series I’m definitely going to return to. Thanks, Xanthe Walter, for keeping me so very well entertained these past few months!