Dr. Georg Poblocki’s office sat at the end of a long hall in a building that smelled of old books and yearning. Dr. Poblocki himself was a large man with craggy cheeks and puffy eyes overshadowed by unruly brows that Evie had the urge to trim.

“The full story behind that drawing you sent was rather hard to find, William,” Dr. Poblocki said in a faint German accent. He smiled with an almost mischievous glee. “But find it I did.”

He drew a book from a stack and opened it to a marked page showing the familiar star-encircled-by-a-snake emblem. “Behold: the Pentacle of the Beast.”

“The police should have consulted you instead of me, Georg.”

Dr. Poblocki shrugged. “I don’t have a museum.” To Evie he said, “Your uncle was my student at Yale before he started working for the government.”

“That was a long time ago.” Will tapped the page. “Tell me more about this Pentacle of the Beast, Georg. What is it? What does it mean?”

“It is the sacred emblem of the Brethren, a vanished religious cult in upstate New York.”

“I forget New York even has an upstate. Seems unnecessary after Manhattan,” Evie quipped.

“Delightful!” Dr. Poblocki smiled. “I like this one.”

“The Brethren?” Will prompted as if waiting out an unruly student.

“The Most Holy Covenant of the Brethren of God. They were formed during the Second Great Awakening, in the early nineteenth century.”

“The second what?” Evie asked.

“The Second Great Awakening was a time when religious fervor gripped the nation. Preachers would cross the country giving fiery sermons about hellfire and damnation, warning of the Devil’s temptations while saving souls during revivals and tent meetings,” Dr. Poblocki said, slipping into the sort of lecturing mode Evie imagined he used with his students. “It gave rise to new religions such as the Church of Latter-Day Saints, the Church of Christ, and the Seventh-Day Adventists, as well as this one.” Dr. Poblocki tapped the book with his finger. “The Brethren was formed by a young preacher named John Joseph Algoode. Reverend Algoode was tending sheep—very biblical, that—when he saw a great fire in the sky. It was Solomon’s Comet coming through the northern hemisphere.”

Evie suddenly remembered the two girls handing her the flyer on the street. “The same Solomon’s Comet…”

“On its way to us now in its fifty-year return. Indeed.” Dr. Poblocki finished. He settled into a chair, wincing as he did so. “This dreadful knee of mine. Old age comes for us all, I’m afraid.”

“I’ll be old before you tell us the story, Georg,” Will pressed, and Evie felt a bit embarrassed by his rudeness.

“Your uncle. He could never wait for anything. That impatience will cost you in the end, I fear, William,” Dr. Poblocki said, peering up at Will darkly, and it seemed to Evie that her uncle looked just a bit chastened. “Pastor Algoode claimed to have had a vision: that the old churches of Europe were a corruption of God’s word. There needed to be a new American faith, he said. Only this great experiment of a country could produce believers pure and devout enough to submit wholly to God’s word and judgment. The Brethren would be that faith. They would rule the new America. The true America. They would fulfill its great promise.” Dr. Poblocki removed his glasses, fogging the lenses with his breath and wiping them clean with a cloth until he was satisfied, then settled the hooks of them over his ears again. “Pastor Algoode brought his small flock to the Catskill Mountains in 1832. They settled on fifteen acres and built a church in an old barn, where they would meet each evening for prayers by candlelight and all day on Sundays. They painted their homes and church with religious signs in accordance with their holy book, and they farmed their land. They had an odd belief system, cobbled together from the Bible—particularly Revelation—and the occult. Their Book of the Holy Brethren was believed to be part religious doctrine, part grimoire.”

“Grimoire?” Evie said.

“A book of sorcery,” Dr. Poblocki explained.

“That explains the sigils, I suppose,” Will mused.

Dr. Poblocki nodded. “Indeed. There were rumors, as there always are in such cases, that the Brethren practiced everything from unsavory sexual practices to cannibalism and human sacrifice. It’s one of the reasons they were so insular and lived up in the mountains—to escape persecution. They did have extensive knowledge of hallucinogens, most likely learned from native tribes who used such things in their religious worship to achieve transcendence. The account of a French-Canadian fur trapper visiting the area tells of ‘a magnificent smoke and a sweet wine which, when consumed, cause the mind to imagine all sorts of angels and devils.’ Now. The Brethren were an eschatology cult.”