Liam had prepared a juicy, appetizing pot roast with a mountain of gleaming potatoes and vegetables, and Jack dug into it gratefully. Afterward, they gathered in Liam’s workshop, around an unfinished dining room table, upon which he had set the safe.

“So?” Nancy asked briskly. “Do we try just keying in the letters of the phrase? In Latin, or in English?”

“Try them both,” Vivi said.

“You’re sure it won’t explode in our faces if we get it wrong?” Duncan asked nervously.

“Only if we try to crack the safe,” Nancy reassured him.

Duncan looked far from reassured, but Nancy just got to it, frowning down at the keypad as she keyed in the long sequence.

The little button flashed red. The door remained locked.

“In English, then,” Nancy said, undaunted. She keyed in the new sequence. The light flashed red again. “Nope.”

They stared at the safe, discouraged. Nancy held up the linked pendants. “Hail queen, mother of mercy,” she repeated softly. “I’ve seen this translation. First Doric mode is a musical term. This was sung, not…oh. Oh, my God. Yes.”

“What?” they all cried out, in ragged chorus.

“Just a minute. Let me get something.” Nancy leaped to her feet and scurried out. She came back moments later, a CD in her hand.

“Novum Gaudium!” she said. “The Gregorian chant choir that I represent! I took Lucia up to see their concert last Christmas, at the Cloisters Museum concert series. She loved it! She even bought the disc.” Nancy pried out the liner notes. “Let me see…it’s a Marian antiphon. The phrase ‘hail queen, mother of mercy’ is the incipit. This is in Doric mode. I wonder if she meant for us to…but how?”

Jack spoke up, his voice hesitant. “I don’t know about music,” he said. “But could the tune have some sort of numeric correspondence?”

Nancy’s eyes lit up. “Sure it could. In relation to the Doric mode, you bet it could. Liam, give me that CD player on the workbench.”

The tall, laconic carpenter unfolded himself, grabbed the player, and plugged it into the wall socket near the table. She selected the track. A haunting tune began. Men’s voices, deep and reverberant, in perfect unison. The sounds rose and fell in ancient patterns that sounded somehow familiar. Nancy listened to a fragment of the piece, brow furrowed. She hit “stop” after a few moments, and let it play again. And again. And again, scribbling numbers after each time.

Around the eighth time, she held up a scrap of paper with a long sequence of numbers. “Twenty-five digits,” she announced.

“Try it,” Vivi urged.

Nancy keyed it in. They held their breath. The light flashed red.

Nancy sagged. “Hell,” she said, dispirited. “I’m all out of ideas.”

“Try adding PDM for Primus Modus Doricus,” Duncan suggested.

Nancy shrugged, and punched in the numbers again. “Okay, guys. Here goes nothing. P…M…D,” she concluded out loud.

The light flashed green. The door of the safe popped open.

Nobody could quite believe it. They stared at the thing, almost afraid of the thin seam of dark behind the crack of its opened door.

Liam touched the door with his finger, and swung it wide. There was only one thing inside. A piece of yellowed paper, in a plastic sleeve. Thin, limp, covered with cramped script. Nancy took it out.

“It’s in Latin,” she said. She passed it to Nell.

Nell put on her glasses and peered at the thing. “This must be Marco’s treasure map,” she said quietly. “A bunch of what look like flower names. Instructions that say to move from this flower to this flower, et cetera, et cetera. At the end, it says to go down into the ground four hand spans and turn three times counterclockwise. No wonder Marco thought the treasure was in the palace gardens. The gardener at the Palazzo de Luca said that they had to dig up the garden more times than he could remember.”

She sighed, and laid it down. “Well, phooey. We’ve exchanged one puzzle for another. And I, for one, am burnt out on puzzles.”

Liam got up. “I’ll go get dessert,” he said, sounding resigned.

Vivi got up to stretch her legs and wandered around Liam’s workshop, touching various items with her fingertip. She turned to Jack.

“This is all Lucia’s stuff,” she told him. “Things that Liam and Nancy were able to salvage from when John trashed her house.” She fingered a mangled thing made of glass, pebbles, plastic, and bent wire. “This is one of mine. The Three Sisters. I think Lucia meant for me to think of it, so it would occur to me to put the pendants together.” She petted the twisted knot of materials and wire. “I’m going to restore this. In memory of her.”

“Excellent idea. Liam’s doing that with Lucia’s intaglio table, too,” Nell said. She laid her hand against the plane of a beautiful carved oak table that lay on the workbench. It was cloven in two splintered pieces.

“This is the famous table Duncan told me about?” Jack asked Vivi. “The one from the Renaissance that had the hidden drawer?”

“Yeah.” Vivi traced some brutal scratches on the surface with her fingertip. “These marks were carved on it by the SS men, during the Nazi Occupation. Colonel Haupt’s men.”

Jack leaned down to take a closer look. “Amazing detail. I can tell in a glance what all these plants are. Common wildflowers, and whoever carved these spent hours looking at them. Look. Centaurea scabiosa. Here’s Achillea millefolium, and Linaria vulgaris, and Senecio jacobea—”

“What did you say?” Nell demanded.

Jack looked at her, embarrassed. “Oh, yeah. Sorry. I meant, knapweed, yarrow, toadflax, and ragwort. And this one here is—”

“No, not that! Repeat what you said in Latin!”

“Oh.” He was taken aback by the sharp, almost frightened look on her face. “Ah, let’s see.” He glanced down at the table for reference. “I just said Centaurea scabiosa, Senecio jacobea—”

“They’re in it! They’re in Marco’s map!” She turned toward the door. “Duncan! Liam, Nancy! Get in here!” She collected the map in its plastic sleeve. Liam, Duncan, Nancy, and Vivi gathered around the splintered table, wide-eyed and breathlessly silent, to watch.

“The first one on the map is Senecio jacobea,” she said. “Ragwort, did you say?” She waited for his nod. “It says to go from there to the nearest Knautia arvensis. Do you see that?”

Jack studied the table, and pointed. “Right here,” he said. “That’s scabious, in English. There are others, but this is the closest one.”

“Okay. Achillea millefolium, then,” Nell said.

Jack’s finger moved down a few inches. “Yarrow.”

A breathless tension was building. Jack was almost starting to feel scared by it himself.

“Do you see anything named Anagallis arvensis?” Nell asked.

“Scarlet pimpernel,” he said, scanning the table. “Right here.”

“And Trifolium repens?”

“Clover,” he said. “Here it is. Down at the corner.”

Nell frowned. “And this is where it says to turn to the earth, and go down four hand spans.”

Jack looked at her. “Go down the table leg,” he said simply.

Vivi looked at him, wide-eyed, and leaned over to give him a kiss on the jaw. “How’d you get to be so smart?” she teased.

“See if I’m right, first,” he said dryly. “Then reward me.”

“Count on it,” she murmured.

Vivi’s sisters exchanged winks and nudges at that interchange, but Liam was already at work examining the carved table legs that lay on another work surface. “I labeled them when I removed them,” he said. “Relative to the direction that the flowers are growing, this one is the front left leg. Right under that clover.” He laid it gently on the table.

Nell leaned over it. “Four hand spans,” she said. “Let’s assume they’re a man’s hands. Liam, measure four, please.”

He did so, and his hand finished up right next to a carved knob adorned with a relief of climbing vines and morning glory flowers.