I had no time to dwell on this unsettling scene, however, for I heard the staccato knock upon the gate that was the prearranged signal for my father’s return. The Master swiftly unlatched the gate, and the pair maneuvered the small cart and sturdy little horse into the garden. Then my father turned to Leonardo, his manner firm.

“I would not have Dino witness what we must do next to carry out your plan. Let him rejoin his fellows.”

“I am of the same mind,” Leonardo said with a swift nod, much to my relief.

To me, he added, “The other apprentices should still be in the small chapel preparing the walls for our next fresco. Make your way there, and if they question you, simply say that I bade you lend them assistance for the day. As for Constantin, you may say that you last saw him leaving the castle grounds with me. Give them no hint that anything is amiss.”

“As you will, Master,” I agreed, sending my father a look of silent gratitude. No matter that I understood Leonardo’s intent, I did not think I could bear to stand by and watch my friend being lashed to the wagon like a bundle.

I took my leave of the garden with more haste than dignity. But even with the gate shut behind me again, I could picture in my mind’s eye what must happen next… the two men lifting Constantin into the wagon and carefully arranging his dead limbs into a cruel mockery of repose. Tied to the seat and wrapped in a cloak, his lifeless form would doubtless pass unnoticed by the guards as Leonardo drove through the castle gates.

I shuddered. I suspected that familiar handling of the dead-no matter that the victim was well-known to him-would not cause the Master much distress. He had examined many a corpse in the time that I had known him; indeed, he was rumored to have secretly cut open dead criminals in the same way that a tanner flayed a beast, simply to further his anatomical knowledge. But as for my father…

Despite my distress, I felt a surge of affection that momentarily warmed my chilled flesh. Though willing to risk confrontation when his principles were put to test, my father’s veins ran with mild humors. I knew that Constantin’s death had touched him greatly, though he barely knew the apprentice. Likely he pictured one of my brothers, or me, when he looked upon the murdered youth. I knew that, while he took part in this charade out of grim duty, his heart was surely wounded by the task.

I left with no backward glance toward the garden, though I did spare several uneasy looks about me as I made my swift way across the broad quadrangle. Surely no one would attempt to strike me down in so public an arena, I reassured myself, taking comfort in the usual bustle of servants and tradesmen making their own way about the grounds. Still, my shoulders twitched in uneasy anticipation of a well-placed bolt between them, and I kept a keen watch for the mysterious robed stranger who might have played a cruel role in this day’s tragic events.

Reaching the main castle unscathed, I headed toward the duke’s private quarters, where the family chapel lay. For the moment, the apprentices were busy setting up the scaffolding within the narrow chamber and preparing the walls with new plaster. No painting had yet begun, for Leonardo had been distracted by his work on the flying machine and had managed but a few sketches for this particular fresco.

At the duke’s direction, the work was to depict scenes from the missing years of Christ’s young adulthood. I had seen some of the Master’s preliminary drawings on the subject and had found them surprising, to say the least. One, in particular, portrayed the Son of God in a strange land populated by elephants and tigers, and with the surrounding temples oddly domed and decorated in bright colors. As for the Christ figure, he was depicted seated with his legs crossed, and seemingly floating high above the ground before an approving crowd of brown-skinned men. I wondered if Ludovico had seen the sketches and if he had approved them.

I rather suspected that he had not!

Cursorily inspected and ushered past by the familiar pair of bored guards who kept watch at the inner gate, I entered the chapel. Within, the apprentices were hard at work with brooms and rags, removing all traces of dirt from the walls in preparation for the layers of fresh plaster to be troweled on during the next few days. Some balanced upon the newly erected wooden scaffolding as they cleaned cobwebs and soot from the eaves; the rest labored at sweeping the lower walls and corner crannies. Though they chatted as they worked, their tone was respectfully subdued as befitted the sanctified setting.

The sleek hound, Pio, was there, as well. Irreverently perched upon one carved wooden pew, he lay on his haunches with long legs stretched before him and paws neatly crossed in the prayerful attitude that had earned him his name. Unlike Il Moro’s men, he appeared quite interested in the apprentices’ work, his bright brown eyes taking in every move, though he obediently kept to his place.

Vittorio was the first to notice my entrance.

“Dino,” he cheerily called, waving his broom in my direction and hopping down from the scaffolding. Remembering that he was in a house of worship, he lowered his voice and went on. “What are you doing here? I thought you were helping the Master and your father.”

Swiping off my cap, I made a quick genuflection in the direction of the altar and then turned to him. “The Master said he did not need my assistance this afternoon and instructed me to help the rest of you, instead.”

“But what of Constantin?”

This question came from Tito, who was perched on the scaffold above us, near where Vittorio had been working.

“We’ve not seen him in some time, not since we returned from the midday meal,” he went on, earning the nods of Bernardo and a few other youths working alongside him. “Do you know where he is?”

“I saw him leave through the castle’s main gate with the Master,” I obediently repeated the explanation that Leonardo had given me. “What their destination was, I cannot say, other than that they left.”

Tito’s pockmarked face took on a look of confusion. “Are you certain it was he that you saw with the Master?” At my nod, he complained, “Why would Constantin leave without a word to us, and without putting one of the other apprentices in charge?”

“Perhaps he felt we are well trained enough that we can perform our tasks without his watching over us constantly,” I replied, making my best attempt at an unconcerned shrug. Then, with a gesture toward Pio, I lightly added, “Besides, he has left a spy in our midst. Pio will surely report our bad behavior should we do anything amiss.”

The hound chose this moment to yawn broadly, his pink tongue unfurling like a bright ribbon. He gave an audible groan and flopped most gracelessly onto his side for a nap. Vittorio and the others snickered at the sight, and even Tito allowed himself a grin. I managed a smile of my own, realizing this might well be the last moment of shared amusement among us apprentices for some time, once news of Constantin’s murder became known.

Shaking off that thought, I grabbed up Vittorio’s broom and vigorously attacked a cobweb. “Come; we must get back to work, lest Pio speak ill of us later. Does anyone know how much plaster we will need to mix tomorrow?”

With my words, the others resumed their earlier tasks. I applied myself to my work, as well, concentrating on the youths’ quiet chatter lest my thoughts drift back to Constantin and the unknown assassin who might still be lurking within our midst. Maintaining my air of unconcern took no little effort, though I was relieved that no one seemed to notice my subdued air and false smiles.

No one, that was, save Pio. After a few moments, he roused himself from the pew and padded over to where I stood. He stared at me with liquid brown eyes and touched an inquiring paw to my leg in an innocent show of canine concern.