Hudson River Homicides, the long-awaited fourth instalment in C.S. Poe’s Memento Mori series, opens, once again, with Detective Everett Larkin confronted with a dead body in a most unusual location. This time, the murder victim is inside a refrigerator which has been dumped in the Hudson River, and scrawled across the door in all caps are the words “PIN ME TO DETECTIVE LARKIN”. So there Larkin is, at just after 11pm, waiting while the fridge is pulled out of the river – and waiting to discover the next step in the increasingly dangerous game of cat-and-mouse he’s being forced to play by his unknown tormentor.

Note: The plotline in Hudson River Homicides is very closely intertwined with those in the previous books in the series, so this is absolutely not the place to start. If you like the sound of intricate, superbly thought-out mysteries combined with a gorgeous, slow-burn romance, then I suggest jumping back to where it all started – Madison Square Murders. I promise you won’t regret it. (And there are spoilers for the previous books in this review.)

At the end of Broadway Butchery, Larkin received another another anonymous, cryptic note telling him to “COME FIND ME”, accompanied by, of all things, a toothpick. That was a few weeks before the discovery of the fridge in the river, and the intervening weeks have not been easy on Larkin. Following the violent showdown at the end of the previous book, in which his boyfriend, forensic artist Ira Doyle, was targeted by a killer, Larkin’s already erratic sleep patterns have become worse as his fears for Doyle’s safety have not only been keeping him awake at night, but have grown into a compulsion to do everything he possibly can to keep him out of harm’s way. If he could, Larkin would even put a stop to Doyle’s involvement in the case – except he knows how that would be received, that, no matter, how noble his intention, Doyle would see it as a betrayal, or a sign that Larkin doesn’t believe he’s up to the task. And there’s no way Larkin can do that to the man he’s come to love more than life itself.

Fast forward to the discovery of the fridge and the body inside – which, unlike the other murders Larkin and Doyle have investigated lately, can’t be classified as a cold case. The ME estimates the woman has been dead for only around three weeks, and when Larkin is able to get a good look at her face he’s surprised to find he recognises her. It’s Mathilde Wagner, the woman responsible for the murder of dozens of Broadway-based sex-workers, for the recent murder of her husband, and for the attempt on Doyle’s life that has Larkin so tied up in knots. Looking closer, Larkin can see the item to which the word “pin” refers; there’s an antique brooch pinned to her tongue, a brooch made from black stone and cut glass that contains strands of braided human hair. It’s another item associated with Victorian mourning culture – and is further confirmation that his and Doyle’s last three cases haven’t been random events, but have all been part of a tangled web of blackmail, extortion, corruption, and murder in which all the perpetrators are connected by a twisted, symbiotic relationship to whoever is leading Larkin on this merry dance.

As in the earlier books, the plotline of Hudson River Homicides is clever, complex and utterly compelling, and you won’t want to put the book down. (I stayed up waaaaay past my bedtime to finish reading it!) The author’s love for and knowledge of New York City and its history shine through as Larkin and Doyle slowly begin pulling together everything they know about crimes new and crimes past, and the bigger picture starts to emerge. And once more, it’s the beautifully drawn relationship between these two damaged but loving men that is the emotional heart of the book. They’ve been together for just over three months, they’re deeply in love and are absolutely committed to one another, sharing a soul-deep connection arising from mutual trust, affection, understanding and unquestioning support. Their relationship is absolutely a two-way street, and the way they care for each other and fight for one another is a joy to read. But their association has already put Doyle at risk, and now it seems that whoever is taunting Larkin has been leading him towards something with the power to wreck everything. Larkin has long known that there is something badly broken buried inside the deeply caring, charming man that is Ira Doyle, and even though he has some idea of exactly what that thing is, Larkin knows that Doyle hasn’t yet reached a place where he’s able to talk about it and start to heal. But by the time Larkin realises where the clues left for him are leading him, he is faced with an impossible choice – does he follow those clues to their logical conclusion and risk breaking Doyle’s already wounded heart? Or does he put the man he loves first and refuse to play the game any longer?

Needless to say, there are some intensely emotional moments in this story that will tug at the heartstrings and/or make you want to throw things (the behaviour of Larkin’s snobby mother certainly made me want to do the latter!), but these are expertly balanced by lighter ones; in the quiet tenderness and affection of Larkin and Doyle’s personal interactions, Doyle’s flirtatiousness, Larkin’s world-weary snark, and the more overtly comedic exchanges with colleagues. And on top of all that, the author finds the space to drop one of the most beautiful – and so perfectly them – declarations of love I’ve read:

Thank you for following me.”
“To the ends of the Earth.”
“Earth is spherical.”
“Yeah, it is.”

The characterisation throughout is excellent. We’ve come to know Larkin and Doyle quite well by now, but they continue to evolve both individually and as a couple, and the small but strongly-written secondary cast comprises a handful of well-drawn new characters as well as the more familiar ones. I was pleased to see CSU Neil Millett again (he and the new ME are definitely striking sparks off each other!) and at the return of Detective O’Halloran who, for all he’s a grouchy fucker, clearly respects Larkin.

The author does a great job of creating an increasing sense of foreboding throughout the story and by the end of the book the stakes – already high – have ratcheted up several notches. Larkin and Doyle may have foiled yet another attempt on their lives and have untangled some of the threads in the murky web of deceit and mayhem they’ve been pulled into, but they’re not given much breathing space before being once again confronted by another demand to “COME FIND ME.”

Tightly plotted, totally gripping, and deeply romantic, Hudson River Homicides was one of my most eagerly anticipated books of 2025, and it absolutely did not disappoint.