“Not a meter, exactly,” he said. “But there is something. Structures on the tips of chromosomes called telomeres. They’re repetitive nucleotide sequences that get shortened every time DNA duplicates. Recently there’s been some research indicating that these provide estimates for how long an organism has been alive and how long it has until it dies. They’ve been doing promising work with warblers on Cousin Island—”

“But those are estimates,” I said.

“As our technology advances,” Chatterjee said, “we are finding them to be alarmingly accurate as indicators of life expectancy.”

“Fine,” I said. “But we can’t tell how old a person is to the day. To the minute.”

“Well…” Ben stood up, his weight creaking the bleacher. “We can’t.”

I felt a tingling under my scalp. “What do you mean?”

“I mean we’re dealing with more than spores and parasites,” Ben said. He hopped down the benches, one after another, then stood at the bottom and looked up at me, Alex, and Patrick. “When I was out there taking care of Britney’s body, guess who I bumped into? Ezekiel. Looks like our ol’ janitor was sleeping off a hangover in the football stadium again, woke up with the commotion.” Ben took a moment to wipe his hands across the front of his shirt, mimicking the gesture that had left those bloody streaks. “So I handled him, too.” With a glance at Chatterjee, he added, “Maybe not as well as our elected leader here could’ve.”

“Why on earth didn’t you say something?” Chatterjee asked.

“Didn’t want to overstep my bounds. But seeing as our leadership is casting about for answers, I figure I’d better speak up now.” Ben started for the doors, waving at us to follow. “You three and the good doctor better come with me.” He turned back to look at us, the crimped skin of his forehead shiny even in the diffuse light of the high windows. “You’re gonna wanna see this.”

Entry 15

ENTRY 15

We halted in the corridor of the humanities wing, bumping into one another. I tried to swallow, but my throat gave only a dry click. The sight before us had brought us up short.

A pale arm thrust across the threshold of Mr. Tomasi’s classroom. Limp fingers touched the floor as if reaching for something.

And they were twitching.

“Wait,” Patrick said. “He’s still alive?”

“If you can call it that,” Ben said.

A dark snake of blood streamed parallel to the arm, polished and gleaming, mirroring back the pinhole ceiling tiles above. The duffel bag containing Britney had been dumped by the lockers; Ben had probably dropped it there when he’d run into Ezekiel.

Alex’s voice cut through my shock. “This whole time we’ve been in the gym? You left a Host out here still alive?”