This article is part of our latest Design special report, which is about crossing the borders of space, time and media.

The French archaeologist and statesman Théodore Reinach spent his family’s banking inheritance to live in exotic magnificence. In the early 1900s, he commissioned a house on a French Riviera peninsula with rooms frescoed in sea creatures and mosaicked with deities — all based on ancient buildings that he had documented on Delos island in Greece.

Mr. Reinach’s property, Villa Kérylos, has been open for decades (in nonpandemic times) as a museum in Beaulieu-sur-Mer near Nice. In recent years, it has also served as a muse for the writer and historian Adrien Goetz. His novel, “Villa of Delirium” (New Vessel Press), blends fictitious characters’ experiences at the Reinach estate with historically accurate descriptions of the building’s evolution and the occupants’ accomplishments and fates.

Mr. Goetz said in an interview that during a 2012 conference at the house, he was transfixed by “so much beauty, elegance, perfection there — it is a pinnacle of architectural intelligence.”

He tried to imagine what Mr. Reinach and his family’s daily lives were like as they straddled worlds by the sea. They were immersed in contemporary politics; they were Jewish and publicly battled against France’s growing anti-Semitism. And yet they surrounded themselves with cohesive décor harking back millenniums, “an homage to Greek thought translated into the very stones,” Mr. Goetz said.

The book is framed as a memoir written in 1956 by Achilles Leccia, an abstract painter in his late 60s from a working-class background. Mr. Goetz said the character was imaginary. Mr. Leccia had been sent as an uneducated but impressionable teenager to live and study with the Reinachs, while the villa was under construction.

His 1956 self, a nostalgic grandfather, returns to his now-decrepit childhood haunts while remembering his married mistress from the 1910s and searching for a lost imperial treasure (no plot spoilers here). His notebook fills with hastily scrawled comparisons of his youthful perspective and the dark secrets that he later learned.

Théodore and his wife, Fanny — in real life, and in Mr. Goetz/Leccia’s telling — lived near equally privileged relatives from the Ephrussi and Rothschild families, who built a pink Florentine palazzo on their patch of Mediterranean waterfront. The engineer Gustave Eiffel, whose nearby Italianate house is wreathed in balconies, traveled in the same cultured circles as the Villa Kérylos’s Jewish architect, Emmanuel Pontremoli.

Mr. Leccia remembers taking drawing lessons from Mr. Eiffel and delightedly watching Mr. Pontremoli and Mr. Reinach ponder design choices for the house. The book describes the architect and the owner obsessing over window latches, tableware modeled after archaeological finds and streamlined blond furniture “with turned feet, bronze scrolls, or huge nails, to give an impression of asceticism and refinement.”

Théodore hosted his brothers Salomon, an archaeologist, and Joseph, a politician who had nearly derailed his career by vehemently defending Alfred Dreyfus (a Jewish military officer accused of treason). Joseph’s son Adolphe, a budding archaeologist and photographer, eventually confides in Mr. Leccia about a family scandal.

The brothers had authenticated a domed-gold tiara said to have belonged to an ancient Scythian king, but when it was revealed to be an erudite Russian goldsmith’s forgery, “everyone was laughing at us,” Adolphe recalls.

During Mr. Goetz’s research for the novel, he was allowed to see the tiara, kept in storage at the Louvre. “It’s the museum’s most incredible fake,” he said. It is considered a masterful interpretation of what Belle Époque collectors, curators and historians wanted the rediscovered past to look like in their dreams — not unlike the Villa Kérylos itself.

In 1914, Adolphe Reinach was killed by German forces in northeast France. Mr. Goetz puts Mr. Leccia in the same regiment at the front, helplessly watching his brilliant friend fall and later suffering his own severe battle wounds. Mr. Leccia also includes mournful and historically correct details of which Reinach and Pontremoli relatives were killed during the Holocaust and how Nazis pillaged the villa.

There is an upbeat note in the last chapter (hint: Boy finds girl while Grace Kelly marries Prince Rainier) and in real life. The villa is so well preserved that for visitors, “It’s as if you could buy an entry ticket any day to visit Atlantis,” Mr. Goetz said. “There are ghosts everywhere.”

He was granted permission to spend a few nights at the house. “Tourists were very surprised to see me pass by with my bag from the Beaulieu-sur-Mer supermarket,” he said. He did not dare to disturb any watchful spirits by using the master bathrooms lined in marble and mosaic, nor the piano hidden inside a lemon-wood cabinet.

At night on the Reinachs’ “almost island,” he said, “I could hear this house creaking, like a boat.” When he opened one empty chest, he added, “it gave off this incredible scent of exotic wood. It’s a smell that has crossed the years, the same that Théodore Reinach breathed in.”