Few things capture the imagination like the concept of hidden treasure. Is there anyone who hasn’t daydreamed of stumbling upon some lost and valuable find—a hoard of Roman coins sitting inches beneath our feet, a Fabergé egg nestling among a pile of junk at a yard sale, a lost canvas masterpiece hanging unnoticed on the wall of a charity store?

Long before Robert Louis Stevenson published his classic novel Treasure Island in 1883, tales of hidden caches have lit up the human consciousness. During the 16th century, Spanish conquistadors searched restlessly for El Dorado, the city of gold; in the 1850s, thousands of gold seekers panned for fortune in the California hills. Later, plundered relics like the Irish Crown Jewels and the Amber Room eluded investigators and would-be discoverers. For all the unfound treasures, though, discoveries continue: the last century has seen the Dead Sea Scrolls, the wreckage of the Titanic, and the burial site of King Richard III all return to human possession.

Yet, the appeal of the quest transcends material gain or historical significance. Each of these hunts holds at its heart a puzzle to solve—and for some, as the pieces below demonstrate, that puzzle can turn into an obsession, even a fatal one. But the promise remains difficult to resist. After all, a hoard of Roman coins was indeed dug up by an amateur metal detectorist, a Fabergé egg was discovered in a flea market, and a lost masterpiece was reclaimed from a charity store. Keep your passport handy: after reading these stories, you may well be tempted to begin sleuthing yourself.

Locked vaults, legendary treasures, ancient archives, curious curses: this compelling case features them all. There’s also some fantastic first-person reporting involved, as Jake Halpern travels to India on the long and complicated trail leading to the locked vaults of Padmanabhaswamy Temple in Thiruvananthapuram, the capital of the state of Kerala. Halpern writes with a strong narrative drive, and his novelistic depictions of conversations and events transport us directly into the scene.

I’ve long been fascinated by Hinduism, a subtle and multi-faceted religion, and it serves as a rich backdrop to the tussle over the future of the temple: a lawyer versus the royal family, neither of whom appear entirely in the right (or in the wrong). The tale unfolds before us in real time, as Halpern visits the protagonists before, during, and after the final revelation. The legal status of deities, priestly divinations, and the modern role of religion all come under debate in a remarkable story full of unforeseeable twists and turns. There are no clear answers, and not every door is literally opened, but this remains an absorbing tale of epic proportions.

I asked Padmanabhan what had made him so confident that there was treasure. “These are all historical books,” he said, gesturing at his library. “It is all here.” He pressed the remote control again, and the clerk reappeared. Padmanabhan uttered a command in Malayalam, the regional language. The clerk squeezed between the back of Padmanabhan’s chair and a bookcase, removed a large volume, handed it over, and vanished. Padmanabhan opened the book to a chapter on the temple, and read aloud a sentence that he had underlined: “A cellar underneath the shrine secures the temple jewels.”