“I was trying to remember.” Alex pulled the phone out to spark his memory. “A lesson our art teacher gave us, about, like, Renaissance artists. How they used to make colors for paint back then. Reds and blues. The pigments were really valuable. They did it by crushing up minerals and even, like, insects and things. Some of the stuff was dangerous, toxic.”

As he pulled up the picture of the rising dead, Alex noticed he was getting a signal on his phone. “It made me think about what you said, about snake venom,” he continued. “The different ingredients your father used in his potion, besides whatever this . . . flower gives him. So, maybe there’s something else he needs, but he can’t get anymore? Like, it’s extinct? But he can get it out from the old paint?”

Alex’s grandfather was silent, navigating a sudden bend. “Not bad,” he said at length. “I should have thought of that. My mind is a little slow at the moment, Alex. But that’s not a bad notion.” He winced as though something unpleasant had been put under his nose.

“You know . . . there was a pigment they used back then, Caput mortuum. Used to be very popular, right up into the twentieth century. Gave artists nice rich browns and lovely, ah . . . flesh tones. And they made that by, well . . . grinding up old mummified bodies.”

“What? Human bodies?”

“Yes. Pieces of people. They’d dig up mummies from Egypt, then pulverize them and mix it all up with—”

“And paint with it? That’s completely gross. That’s horrible.”

“Well, yes. But galleries are full of it, Alex. Bear that in mind next time you visit a nice posh museum. Point is, though, it was the ancient Egyptians who first got really serious about the whole immortality game. My father had an entire section of his library devoted to early Egyptian texts, techniques for eternal life. Now, I have a friend in Berlin, a scientist. If we can get the painting Harry saved to her lab, we could run some proper tests, try out your theory, and some others. I wonder . . .”

His grandfather fell silent. There was one new message on Alex’s phone. From Kenzie. Sent a few hours before:

Look out your window.

Alex glanced to the side, then behind. Nothing.

“Harry,” he said after a bit. “I’m sorry I couldn’t.”

“You’ve nothing to be sorry about, Alex. I know you tried. I’m sorry for asking.”