Minutes later, Arturo reemerges, holding a cup and saucer. She bites back a grin when she sees the two biscotti on either side of the cup, resembling something her grandmother might have served. He sits down across from her. “How can I be of assistance?”

“You’re aware of the legend of the San Giovanni rats, right?” Alana asks. “And the crypt that housed them below the church?”

“Yes.” His brow furrows. “Mainly from Brother Silvio, of course. He was our unofficial historian. The legend, it dates back to the Middle Ages.”

She sips the espresso, enjoying the rich, bitter bite. “Brother Silvio gave me a copy of that medieval doctor’s diary.”

“Ah, yes, the diary. I read it, too. With all the nonsense about the Custodi di ratti and rat worship.”

“You didn’t believe it?”

“No.” He smiles. “None of us did. It’s merely superstition. Typical for the time.”

“And yet the brothers have been feeding those rats down the scivolo ever since.”

“Feeding them?” He laughs. “No. No. It was how we cleared our table scraps. The ancient ritual was a practical one, too.”

She lowers her cup. “We found a rat that was carrying the plague, Don Arturo.”

He shrugs. “It only makes sense.”

“It wasn’t just any rat. We suspect the animal is a direct descendant of the medieval rats Pasqua describes in his diary. The ones from the crypt.”

He frowns. “They couldn’t have survived. Not all this time.”

“We have reason to believe they did.”

“Incredible,” he mutters. “And you are suggesting this has led to our city’s epidemic? Because the builders freed the rats from captivity?”

She nods. “Except we’re not entirely sure who freed the rats.”

The creases around his eyes tighten. “I do not follow, Dr. Vaughn.”

“The plague has spread to other cities, too. We know it was brought to Rome by a man with a chest infection. But Naples is a different story. It couldn’t have spread there by human contact. And no rat alive can wander four hundred miles in just a few days.”

Arturo gapes at her. “You are telling me that someone deliberately transported an infected rat from Genoa to Naples?”

“We believe so, yes. So we need to figure out who else knew about the crypt and what exactly it housed.”

He looks down in silence, digesting the news. “Most of the brothers would have heard the stories. A few would have read the diary. But if you are suggesting . . .”

“We have to consider it, Don Arturo,” she says with genuine sympathy. “Were any of the monks particularly interested in the legend of the crypt?”

He pauses for a moment. “No. None that I can think of.”

Alana leans forward. “Some of the brothers must have been upset when they heard the monastery was going to be torn down.”

“Yes, of course. We all were. I was, too. It was our home.”

“Can you think of anyone who was particularly upset or . . . behaving strangely around the time the monastery closed?”