As part of the Frieze Projects program at the second annual Frieze New York fair (May 10-13), curator Cecilia Alemani commissioned The Vault from Los Angeles-based artist Liz Glynn, known for sculptural installations and interactive performances. In theory, 200 visitors per day would be randomly selected to receive a key, upon entry to the fair, to a speakeasy-style cocktail bar tucked away somewhere in the fair. The secrecy and exclusivity around the bar lent an air of intrigue and suspense.

My key was an unexpected gift but by no means random, since it was procured for me by a friend of a performer in the piece. The small blue envelope read, "The Unmarked Door to THE VAULT is here: C36 X C34." During my visit to the fair on Monday, I learned in searching that this definitely did not mean C35, but a white door blending into the wall between the stand of Los Angeles gallery Marc Foxx and that of Paris's Yvon Lambert. From behind a slot in the door, a mouth spoke to a gentleman waiting in front of me.

"Don't you know how to read? Show me your number!" barked the unseen doorman. I showed it to him. "I'm not even talking to you," he jeered. The man ahead of me was afforded entry, while the door shut in my face. It was a Monday afternoon on Randall's Island but I felt as self-conscious as if it were Friday night in front of a club in SoHo.

I removed from my envelope a white card that read "knock three times slowly" and a key with the number 50 on it. I performed the secret knock and the doorman greeted me anew. "Show me the number." From behind the open slot all I could see was a toothy grin. He opened the door and led me into a compact, windowless chamber. As my eyes adjusted from the Frieze tent's miles of whiteness to this bare darkness, I made out a wall of small, locked boxes like in a bank vault, clarifying the title of the piece. The doorman took my key and handed it to a hostess, who unlocked a box with the corresponding number.

Carrying the box, she led me across the room to a makeshift bar. The darkness, discreet entry and conspiratorial tone of the people flanking me might otherwise have been signs to flee, but for a cocktail at Frieze, I was game. The speakeasy may be romanticized in popular culture, but it's not often you get everyone playing their parts so convincingly, including me as the confused and slightly anxious patron.

In a worn but stylish velvet vest and retro cat-eye glasses, my hostess-cum-barkeep removed from the box a small martini glass, a leather strap and a black wooden triangle. Setting the triangle down, she took the glass and, without my saying a word, started on a vodka concoction while beginning a brief story about a detective and a serial killer.

Like the cocktail, this Raymond Chandler-style murder mystery seemed all of her own making, though there was a system to the story. Glynn had the bartenders gather inspiration and cues from the items in the box while working from Jorge Luis Borges stories they'd memorized. There was also, like at any good cocktail bar, a specially designed menu. With the triangle she told me how the detective caught the murderer (every three killings would create an equilateral triangle on a map-too predictable). With the coiled leather strap she told me how he should have laid out his crimes (by structuring his trail of crime like a labyrinth). The conclusion of the story perfectly coincided with the pouring of my drink, which was a tidy way of saying, "You're done here."

I was then led behind the wall of the bar to find a similarly dark setting in which to enjoy my drink. A long wooden table filled the blank, dreary space and I was welcomed by a small group of people already enjoying their beverages. I would have loved to know how everyone got their keys, but I settled for everyone comparing stories told them by the barkeep. From a cowboy who gets depressed after he finds a playing card in the desert to a civilization very annoyed by a perfect map, the tales were perplexing but perfect for this mysterious speakeasy. The drink was delicious, something I'd probably never order. It had flavors I couldn't really put my finger on, which made sense for a bar that most people probably never knew existed.

PHOTO: The doorman greets some speakeasy visitors at Frieze on Saturday. Photo Brian Boucher.