A Letter from the Lonesome Shore is the conclusion to the much beloved Sunken Archives duology by Sylvie Cathrall that began with A Letter to the Luminous Deep and it follows the largely epistolary nature of that book.
E. and Henerey who began their unique courtship through correspondence find themselves transported to an enigmatic underwater city and with no clear pathway to return home they strive to do what any good scholars would and learn more about the city and its society. Meanwhile E.'s sister Sophy and Henerey's brother Vyerin, who had begun a correspondence of their own embark on a quest to save their siblings.
If you enjoyed the first book in this series you will find plenty to enjoy here, from the epistolary style and the charming relationship between E. and Henerey to the elegantly descriptive writing style and the mental health representation. This all worked well for me, what was not quite so much to my taste was how the story wrapped up, it felt somewhat rushed, especially given the gentle pacing of the series as a whole. I also thought that things felt a little muddled in the middle as it took some time to get to grips with the new characters that are introduced here and figure out how they played into the story as a whole and there were some aspects of the setting that did not feel fully defined and some parts of the story that did not seem fully fleshed out in the way that the world of the first book did.
3.5 stars rounded up.
I read and reviewed an ARC courtesy of NetGalley and the publisher, all opinions are my own.

I really enjoyed this book, the format through letter really works for me because it feels more personal. I love the core cast of characters and I’m really happy with how the story developed for all of them. I wasn’t really sure in the structure since I’d have liked to have both timelines in the first half, but it did make sense in the end. I’m not really sure I loved the ending, which is why this is not a five star for me, however I’m really happy with how this story went. E. and Clel have my heart though, all their moments together were super cute and I felt seen just like in book one with their way and difficulty in expressing themselves.
Thank you NetGalley and the publisher for an e-arc copy in exchange for an honest review.

Sylvie Cathrall’s A Letter from the Lonesome Shore is a thoughtful conclusion to the Sunken Archive duology— both whimsical and wistful, with a deep appreciation for language, relationships, and the beauty of curiosity. While not without its flaws, this sequel still offers a rewarding journey for those who fell in love with the quiet magic of the first book.

Picking up with E. and Henerey’s story in an underwater city that feels like a cross between a scholarly retreat and a dreamscape, the novel continues its format with care. The romance between E. and Henerey remains a highlight—soft, affirming, and quietly profound. Watching E. grow into herself with Henerey’s gentle encouragement is especially touching. Their dynamic continues to be full of subtle charm, and the ace representation is handled with the same grace and warmth as in book one.

New and returning characters—especially Sophy and Vyerin—add layers of found family and quiet resilience, and their journey to reunite with E. and Henerey provides some of the most emotionally resonant moments in the story. The bonds of friendship, siblinghood, and shared purpose are at the heart of this novel, and they shine through even when the plot occasionally gets tangled.

That said, the story does struggle at times under the weight of its format. As more perspectives are introduced and timelines weave together, clarity sometimes suffers. It can be hard to keep track of who is writing to whom, and when, and while the prose remains elegant, the density of the letters and long passages can feel like wading through literary fog. There were moments when I wished the narrative had loosened its commitment to the epistolary style just enough to let the story breathe a little more naturally.

The central mystery—while intriguing—feels slightly underdeveloped by the end, and some of the worldbuilding threads, especially regarding the Structure and the cosmic threat, remain elusive. That sense of unfinished business may frustrate readers hoping for tidy resolutions.

A Letter from the Lonesome Shore may not have the same fresh magic as its predecessor, but it remains a beautifully unique piece of magical academia. For fans of thoughtful fantasy, tender romance, and stories that prioritize emotional truth over plot mechanics, this is a fitting farewell to a world unlike any other.

This was a very anticipated sequel for me this year and I was so happy to return to this world. Sylvi Cathrall's use of language is beautiful and her characters are fantastic. This is a lovely and whimsical series that I would recommend to anyone who wanted a cozy fantasy but with a more sci-fi or speculative feel.

I really enjoyed the first 30% of this book. It was mostly delightful, and an improvement on the first book. I found it a lot easier to follow, and it finally felt like the characters had their own voices.

I believe the fact that there was also some dialogue and it wasn't just long paragraphs of letters definitely helped.

I also found this delightfully funny, the formal language worked so well with the humour.

But things went significantly downhill for me pretty early on. More characters and perspectives were introduced, and I became lost again. No one had an individual voice and I lost track whose letters or diary entries I was reading, especially as the chapters were so very long.

The way things were revealed made little sense too, and timelines were so confusing. The whole Predator angle seemed ridiculous, so far fetched, and a backstory was introduced so late that I lost hope we'd get any information about the world at all. This book could be really phenomenal, but the lack of quality world building seriously impacts it negatively.

The plot was weird, barely there actually. I wanted to love this, but I can't help but feel like this is in no way a fully polished book.

The best thing about this duology, by far, is the representation of mental health struggles by both main characters. This was portrayed beautifully and respectfully. The romance improved too, and I just adore how E. and Henery's relationship progressed, the charming way they turned out to be just what the other needed.

The ending left me slightly disappointed, as it didn't feel like we got any real closure. But as a story with academic vibes, expressing a deep love for the ocean, this hit the mark.

Thank you NetGalley and the publisher for gifting me an early copy of this book.
I enjoyed going back to this world and was excited to pick up where we left off!
It was great to meet new characters, places and have some answers to the mysteries that were left in book 1.
I still LOVED E. and Henerey’s relationship and how they talk, it was just the CUTEST. It felt nice to see that they are taking the time to get to know each other and respect the boundaries that the other might have.
I enjoyed this one, but I think I preferred the first one. Probably because the concept and ideas were new then, but book 2 is still quite good and I would recommend it if you enjoyed the first one.

An epistolary novel full of love, mystery, and a search for knowledge - this sequel will take you through oceans unknown, and it's definitely a memorable experience.

Unfortunately, I think the first book was the more magical of the two, as the epistolary form fit the plot perfectly and the atmosphere was so uniquely built. A Letter to the Lonesome Shore doesn't ever get the same world building details as the correspondence bounces between different times, characters, and settings in a less directed way. It was a bit harder to follow at the beginning because of this, and at points the letters felt like they were pushing my belief in terms of what was included for dialogue and detail - it felt like it wanted to be told in real time but knew it had to stick to the established format.

That being said, I adored the sections revealing what happened with E and Henerey. Their romance is delightful and the ace rep was wonderful. It was fantastic getting to see E grow in confidence especially!

While the threat was intriguing, it didn't feel fully dealt with which rumbled my feathers a bit, especially as this is the final book in the series. I really wanted more answers on the whole...
However, the ending was beautifully bittersweet and very fitting (I would LOVE a follow up that just centers around the island!), and the fierce family bonds that shine through the whole narrative were so charming to witness and gave such a cozy feel to this story.

Overall, while the sequel didn't hold the same magic as the first, I was still entranced by this underwater world. The characters are special and I know they'll be in my mind for a long time to come.

I very much enjoyed A Letter from the Lonesome Shore. I read A Letter to the Luminous Deep last year so was very excited to see where the story went and what happened to E and Henerey.

The things I loved in book 1 were the same things I loved in book 2. The personal letters between partners or siblings were my favourite. They were easy to follow and felt genuine and true to their relationships and any struggles they may be facing.

I loved watching E and Henerey’s relationship strengthen and evolve. Their communication by letter continued despite being with each other which was very sweet and endearing.

I also loved reading about the development of Sophy Vyerin’s friendship.

As with the things I loved, the things I struggled with in book 1 were the same for book 2. Some of the technical parts I really struggled to follow and found slow. I had to re-read some sections more than once.

Overall I enjoyed the story and the conclusion to The Sunken Archive duology

Thank you to the publisher and NetGalley for the review copy. I was so eager to go back to the story of Henerey and E after loving the first book, and while I did really enjoy the sequel, it did not quite capture that spark of magic I felt reading the first book. I think this is partly because the storyline does become perhaps slightly too complicated and that the nature of the events did not lend themselves quite so well to the very unique format. I still love all of the characters from the first book, and the relationships and mental health representation are some of the best I have read. I do highly recommend this duology. It is a very interesting blend of fantasy and science fiction that I hope many will enjoy.

It was a joy to go back to this world and these characters!

I loved A Letter to the Luminous Deep, it was one of my favourite reads of 2024, so A Letter from the Lonesome Shore was possibly my most anticipated release of 2025, and it did not disappoint! I was itching to return to this underwater world and learn more about E. and Henerey's fate, Sophy and Vyerin's quest, and find out the end to this story that Sylvie Cathrall so magically started in the first book. The epistolary format continued on, and I enjoyed the addition of missives from some new charming characters. The diversity and disability representation within this book is fantastic, and incorporated seamlessly and respectfully in the story.

E. and Henerey were once again completely endearing characters, and I don't know how many times their sweet, innocent, and wholesome interactions made me sigh and smile. I loved how naturally their relationship kept developing, and the comfort and confidence they found together. I especially enjoyed seeing E.'s character development, I could feel her happiness through the pages. I found the parts about the voyage that Sophy, Niea, and Vyerin embark on very enjoyable, and I would have liked even more of them! I love Sophy and Vyerin's friendship, how important they became for the other and became family. The Thirtieth Second Scholar was a lovely new character, she was very endearing and funny, and I liked their dynamic with the Fifteenth First Scholar. The rest of the Scholars' behaviour felt very dramatic at times, and once their reasoning was exposed, I felt it didn't completely justify their behaviour: I just was not convinced that their course of action was the only or even the best option.

I overall liked the story line, but I did find it a little bit difficult to follow. It got a little bit overcomplicated at times, and I had to stop a few times to make sense of it in my mind; that's the reason why I'm not rating it 5 stars. I did find it very original though, and I enjoyed the ending, it was in fitting with the rest of the story. I am sad that this duology is finished and I have to bid farewell to these characters, but I will definitely reread these, and I am looking forward to seeing what's next from the author!

Thank you so much to NetGalley, Little, Brown Book Group UK | Orbit, and Sylvie Cathrall for the opportunity to read an ARC in exchange for an honest review!

'A letter from the lonesome shore' is the second and final book of a duology. I loved the first book, despite the epistolary format (something I tend to struggle with) and an overall pacing that meander very quietly rather than flowing like most book do today. This second book work with the same premisse, I loved it. I might be a little less enthusiastic compared to book one, but that mainly because of my tiredness and the dislike I had for certain scholarly characters. They were so caught up in their rules and ideas, which was well done and well thought, but clearly annoyed me.

Nonetheless, it was a delight to find E., Henery, Sophie and Vel again, as well as the other characters. Following their journey and adventure through their letters, learning pieces of information and putting it together and seeing them grow was great fun.

I was curious to see where the story was going, what stakes were lingering in the dark. I really appreciated the ideas and how they were executed. Sure, this duology isn't for everyone. The epistoalry format, written in a very victorian or scholarly way, can be offputting, as is the pacing. But it work for the story, in my opinion. It especially work for E. and Henery, their internal struggle, their fears and strength. And without saying too much, it also gives the ending a special turn, the height it needed. The story works well as a romance but also an exploration of academic pursuit and the human nature, especially around the question of knowledge and school of thoughts.

Very glad I was able to read this book before its release!