A baby-faced agent leads Alana to an inner office. Sergio sits behind a desk with the phone to his ear, but he waves her inside. As she sits down across from him, he shoves a photocopy of Stefano Russo’s passport across to her.

“You work fast,” she says as soon as he hangs up.

He nods. “Especially considering how many Stefano Russos there are in this city.”

She notices his birth date. “He’s only twenty-five.”

“Old enough.”

“Have you tracked him down?” she asks hopefully.

“No. We’ve alerted the police and other intelligence agencies across the country. And we just released his photo to the media.”

Alana thinks of the possible consequences, but her resolve doesn’t waver. “Good.”

“Brother Stefano has no cell phones registered to his name. He doesn’t appear to use any bank or credit cards. We haven’t even found any social media or email accounts for him.” Sergio lifts another page off his desk and passes it to her. “We do have this.”

Despite the Italian wording, Alana recognizes the printed form as a typical electronic medical record that many regions use to track patients’ pharmaceutical histories. She studies the names of the medications on the list, most of which are the same or very similar in English. She taps two of the items near the top of the list. “These antibiotics—ciprofloxacin and doxycycline—are both first-line treatments for Yersinia.”

Sergio frowns. “Do you think he has been infected by the plague himself?”

“Look at the dates. They were prescribed over a month ago.” She takes a closer look. “And check out the quantities! He was given a three-month supply of each.”

“Is that a lot?”

“Yeah. Normal treatment would be for a maximum of two weeks, but . . .” She snaps her fingers. “Prophylaxis!”

“I don’t understand.”

“Stefano has enough antibiotics to protect himself for months from getting the plague. Because he knew he was going to be exposed to it for a prolonged period!”

Sergio studies the page for a long moment and then finally nods. “Yes, I think so, too. To protect himself while he was carrying infected rats.”

She taps the page again. “We need to talk to the prescribing doctor. Dr. Giannini. He or she might know something.”

Sergio nods and reaches for the sheet, but she pins it to the desk with her hand. She runs her finger down to the medications listed below the antibiotics. “Look at these other drugs: lithium, olanzapine, and sertraline.”

“What are those?”

“Psychiatric medications.”

“For what?”

“Has to be some kind of psychotic disorder. They were prescribed by a different doctor. Dr. Lonzo. Probably Stefano’s psychiatrist. We need to speak to him, as well.”

Sergio makes a phone call and, a minute or two later, gets one in return. He stands up from the desk and adjusts his dark tie as he closes the top button of his navy suit. “We have the doctors’ addresses,” he announces.

They head down to the garage and his car. Sergio drives them eastward to the same neighborhood as the Ospedale San Martino. He parks over the sidewalk in front of a medical building that has an outpatient clinic on one side and a pharmacy on the other. They rush through the clinic’s crowded waiting room and up to the desk of a harried-looking older receptionist. Sergio and the woman argue for a few minutes before she throws up her hands in defeat and stomps away. Moments later, a young doctor with a messy mop of dark hair and a short white coat, who appears as stressed as his secretary, follows her into the reception area. Dr. Giannini guides them down a narrow hallway and into a small office that is equipped with an old-fashioned examining table and a blood pressure cuff mounted on the wall.