If reality really could be controlled by our thoughts, I would have melted the prison walls and walked out into the cold winter day. But I wasn’t a brilliant physicist and I couldn’t control much of anything.

Days passed. I touched every single stone in the cell, no matter how slimy, desperate to find a touchstone. I added my scratches to the marks already on the wall. I closed my eyes and tried to think my way out. I cried until I was too exhausted for any more tears. And I ate wormy gruel even though I swore I wouldn’t touch the filthy stuff. How would I ever escape?

You know those stories about kidnapped people and how they stay sane by reciting the alphabet or any poems they’ve memorized? Let me say, that didn’t help at all. Instead, I sang every stupid camp song I could think of. I had long conversations with Mom, Dad, and Malcolm.

But mostly I drew. I still had my sketchbook with me, and I drew everything I could remember from when we first got to Rome. From the ragwort to Bruno’s face. I thought about what Malcolm had said, that he thought I was talented. If I ever get out of here, I promised myself, I’ll show him these sketches. He’ll get to see sixteenth-century Rome himself.

The sun was high in the small window on the third day, and I could hear many footsteps, when the door opened again. Two soldiers shoved past Francesco, each grabbing me by an arm.

“What’s going on?” I yelled, trying to twist out of their grips. “I’m innocent!” I’d forgotten why I’d been thrown in prison in the first place—oh yeah, the wine jug, the sbirri, the plate of artichokes.

“You’re getting out of here!” snapped one soldier.

“You should be happy about that!” sneered the other, pushing me out of the cell. I bumped into a filthy man with matted hair and crazy eyes, another prisoner. There were a dozen of us, plus as many soldiers.

“Where are we going?” I whispered to a boy about my age.

“To the galleys!” he hissed back, his eyes round with fright.

“What’s that?” I asked, though clearly the answer wasn’t good.

“Ships! We’ll be slaves, chained to the oars and made to row until we die. They might as well kill us right now!”

I’d thrown a jug at a policeman and I was sentenced to slavery for that? I hadn’t even had a trial! Could I get word to Del Monte? Could Morton save me? Maybe I could find a touchstone. The soldiers hadn’t bothered to tie my hands, so that was my only chance.

We stumbled out of the prison gate into the daylight, momentarily blinded by the bright winter sun. I gulped in the cool, fresh air, an intense relief after the dank, stale stink of the last few days. Even though we were on our way to slavery, being outside was freeing.

I had to find a touchstone before we got to the ships and disappear my way out of the punishment. The soldiers walked in front, alongside, and behind us, using their sharp halberds to poke anybody who stumbled on weakened legs. How could I get past them? I hadn’t eaten or slept well for so long that I couldn’t count on outrunning anyone. I’d never been very fast even when I was well-rested.

You think you can bear anything, that you’ll be defiant and fight your way out of terrible situations. Then when they actually happen, you find out how easy it is to give in, how hard it is to stay determined and strong. I thought of Bruno, how he didn’t deserve to die, how I didn’t deserve to die, and somehow that gave me more energy. There had to be a chance for an escape, and when I saw it, I’d take it.

We were walking toward the Tiber River, where the boats waited for their slave crew. We were almost at the bridge when a man pushing a cart piled high with onions slipped and tipped his cart. I didn’t understand how something so heavy could fall over, but there wasn’t time to figure that out as onions rolled under, around, over everything.

“My onions!” The man pushed though the soldiers, through the prisoners, racing to collect as many as he could. The starving prisoners grabbed the onions, too, some even biting into them right away. The soldiers tried to keep control of both us and the onions, yelling at the merchant for being such a clumsy idiot.

“Out of my way!” The onion man shoved me hard. My hip crackled where he’d touched me and I recognized the disguised figure, the voice. It was Mom!

I wanted to grab her, to hug her, but I knew what she was doing. I took the chance she gave me and sprinted over the bridge, ducking into the first side street I saw, turning corners, twisting through the alleys. I ran until my legs burned and my lungs ached. Long after anybody could have been following me, I kept on running, pushed on by panic.

Careening wildly through the streets, I found myself back at St. Peter’s. Here, finally, I stopped to catch my breath, my legs feeling wobbly from sprinting. There in the piazza in front of the great dome was an obelisk. And on the ground around it, the symbols of the zodiac. It was both obelisk and meridian, marker and sundial.

Relief surged through me. It could be a touchstone. I thought about what Bruno had said—how our perceptions shape reality. Could I make the obelisk a touchstone by believing it was one?

“Halt!” a gruff voice yelled. The soldiers had found me. I pushed down the terror rising inside me and focused on the obelisk. I forced myself to think of Dad and Malcolm as I reached out and touched the carved marker, looking to see if Mom was behind me. But all I saw was smoke billowing around me, sucking up marble, stone, and dust, spitting out earth, wind, and fire. I was spinning in a haze of colors, of dawns and dusks, starry nights and blazing days.