Opening Passage: Narratively, either the Foreword or Chapter 1 can be treated as the beginning of the book. From the Foreword:
The year was 1902. While strolling in the Bois with his daughter Véronique, the well-known scholar of the megalithic monuments of Brittany, M. Antoine d'Hergemont, was assaulted, and Véronique abducted, by four men. This came to be called the Hergemont scandal.
From Chapter 1:
Into the picturesque village of Le Faouet, situated in the very heart of Brittany, there drove one morning in the month of May a lady whose spreading grey cloak and the thick veil that covered her face failed to hider her remarkable beauty and perfect grace of figure.
The lady took a hurried lunch at the principal inn. Then, at about half-past eleven, she begged the proprietor to look after her bag for her, asked for a few particulars about the neighbourhood and walked through the village into the open country. (p. 1)
Summary: Véronique d'Hergemont was once kidnapped and forced into marriage by a man named Count Alexis Vorski; the marriage led to a son, François. Véronique's father fled with François but they were lost at sea and presumed dead, leading Véronique to withdraw in grief into a Carmelite convent, in 1905. But in 1919, when watching a film about Brittany, 'A Breton Legend', she happened to see a door with the initials V. d'H. in what looked like her own handwriting, despite her not remembering ever having written. She investigates, and begins to find herself in a complicated tangle of mysteries. These mysteries lead her to the island of Sarek, a strange island off the coast of the most superstitious part of Brittany. Sarek is also known as the Island of the Thirty Coffins, the 'thirty coffins' being a complicated series of reefs that surround the island and make it difficult to approach. There are many strange legends associated with it, and Sarek is in fact chock full of Gothic Romance tropes. The island is associated with Druids, and has a lithic structure, the Fairies' Dolmen; it has a ruined Priory from a medieval monastery. There is a cave system on the island. There is a garden on the island, known as the Calvary of Flowers, in which the flowers grow strangely large and vibrant.
Most importantly, the locals are terrified of the island, and it is associated with fragments of prophecy about the thirty coffins having thirty victims and a four women being crucified and a miraculous stone, known as the God-Stone, that can kill and heal. In the course of her investigation, Véronique discovers a drawing by her own father of the illustration in an old manuscript concerned with the prophecy; one of the four crucified women has her own face, and is identified by the initials, V. d'H. And it will only get stranger from here, until Don Luis de Perenna -- better known as Lupin -- arrives to solve the mysteries.
When we look at reviews of this book, it tends to get a love-or-hate response. The first third of the book at least is quite slow-moving; the story is structured so that there are many pieces that have to be put into place. This clearly loses it a lot of readers. Once things begin moving, however, they move quite quickly. Lupin's role in the book is really as a deus ex machina rather than anything else; Lupin ends the book, in fact, reflecting that a novelist could have written a version of the story that did not involve him. (My suspicion, albeit based on very little, is that this is Leblanc commenting sarcastically on the fact that readers keep wanting more Lupin, despite there being so many other stories to tell and hinting at the novel he actually had wanted to write.) Personally, I found the book quite fun, especially once the pieces were all in place. I had no problem with Lupin's being the external resolver. The book is in the genre of apparently supernatural mysteries that turn out to be not so supernatural; these are often not very convincing, but I think this was handled quite well.
There are many mysteries to the Isle of Sarek, but I think it does not give away too much of the story to remark that the book is the book it is because it was written in 1919. In 1898, the Curies discovered radium, and were able to isolate the pure form in 1910. A few things were known about it, but radioactivity was (for obvious reasons) difficult to study, and radium in particular is difficult to gather together in large amounts. And the early bits and pieces that anyone could put together made radium, although already known to be potentially dangerous seem to have immense potential for a large number of things, if you just used correctly or in the right doses. In 1918, for instance, you have the development of the patent medicine, Radithor, which claimed to cure a number of illnesses with a solution that included traces of radium. This was the one of the early entries into what later became known as the Radium Fad, in which radium showed up in all sorts of medicines and cosmetics, extraordinary effects being attributed to its radioactive powers, which, after all, were not any kind of superstitious miracles, but were scientific facts. It wasn't until the 1930s that the Radium Fad began to crash. This happens to be historically important in the United States, because Radithor's demise in a scandal in which one of its major advocates died of radiation poisoning led to a massive expansion of powers in the Food and Drug Administration and a great deal more regulatory caution about medicines and cosmetics.
All of this is to say that the story was written in that exciting time when radium was seen as having limitless potential, near the very beginning of the Radium Fad. Scientific magic, scientific miracle, sweeping away superstition. It's not magic, it's vita-rays! Of course, we know now that it was all a sort of superstition itself (although we have certainly not in general learned the lesson that what we replace superstition with is often just a new kind of superstition). But that was in the future. The romantic possibilities of it had not yet crashed into disillusionment, and I think it works well as a science fiction thriller for its day. And frankly, I like how it meshes with the Gothic atmosphere and folkloric elements.
Favorite Passage:
"They are very complicated legends," said Stéphane, "very obscure traditions in which we must abandon any attempt to distinguish between what is superstition and what might be truth. Out of this jumble of old wives' tales, the most that we can disentangle is two sets of ideas, those referring to the prophecy of the thirty coffins and those relating to the existence of a treasure, or rather of a miraculous stone."
"Then they take as a prophecy," said Véronique, "the words which I read on Maguennoc's drawing and again on the Fairies' Dolmen."
"Yes, a prophecy which dates back to an indeterminate period and which for centuries has governed the whole history and the whole life of Sarek. The belief has always prevailed that a day would come when, within a space of twelve months, the thirty principal reefs which surround the island and which are called the thirty coffins would recieve their thirty victims, who were to die a violent death, and that those thirty victims would include four women who were to die crucified. It is an established and undisputed tradition, handed down from father to son: and everybody believes in it. It is expressed in the line and part of a line inscribed on the Fairies' Dolmen: 'Four women crucified,' and 'For thirty coffins victims thirty times!'" (pp. 122-123)
Recommendation: Highly Recommended, although, as noted above, mileage may vary. The book is explicitly a sequel to The Golden Triangle, and I think parts of the story work better if you have already read that book.