“What’s the chaperone’s name?” I asked, still jotting down notes. I wanted this to be a great story, but it was so complicated, and although I was good at pretending, I wasn’t sure I really understood what he was talking about.

“My chaperone is a very unusual protein, known as a prion. No one knows precisely why, but these prions are capable of getting past the blood-brain barrier. So if we can tether a virus that will make neurotrophin to the prion, we may be able to slip it into the brain in large enough quantities to cure these horrible diseases—just as we have cured the mice.” He lowered his voice. “But I must tell you the truth: there is a problem with my solution.”

Dr. Navarre glanced toward the door to make sure the press officer was still outside the room. “My colleagues at Unetat do not seem interested in understanding this problem—they are dreaming of the billions of dollars they will make with a cure for Alzheimer’s disease—but it is quite real. These prions may be lifesaving chaperones, as I hope. But mutant forms also seem to cause the worst brain diseases of all—the spongiform encephalopathies—which can leave the brain riddled with holes. These diseases are quite terrible. The victims suffer loss of coordination and then dementia. My colleagues would be very angry if they knew I had told you this. But it will help you to understand why we are far from having a cure for anything.”

A dark cloud of ordinariness had suddenly descended. Dr. Navarre hadn’t found a miracle, after all. I asked him a few more questions about how his treatment would work, assuming the prion-chaperone idea turned out to be safe. He answered with careful explanations I didn’t entirely understand, and gave me several scientific papers he had written that he said would clarify certain points—which I suspected I also wouldn’t understand. My hopes of getting a story on the front page—or even on the front of the science section—were vanishing. I was actually grateful when the press officer returned.

“I’m sorry,” he said. He had lost his earlier officious self-assurance; his face was flushed and his hand movements were agitated. “We must end the interview. There is a problem in Paris. The police are warning people. Something has happened near the Champs-Élysées.”

“But he is our guest,” protested Dr. Navarre. “He may have more questions.”

“What’s going on in Paris?” I asked. It sounded like actual news. I didn’t want to be disrespectful to my new friend the scientist, but he and his halfway cure for Alzheimer’s could wait. They were not yet a story, at least not for The New York Mirror.