Chapter 60
Not quite perfect . . .
Missing number . . .
Ivy was too tired to figure out the riddle.
The last two numbers, at least, were self-explanatory: they were GPS coordinates.
Outside Dr. Moorehead’s office, she spotted one of her colleagues. One of the few other female professors in the math department.
“Hey, have you seen Dr. Moorehead?” Ivy was having a hard time speaking. Her throat was raw and bone-dry.
“He left about an hour ago.”
“Know where he went?”
“No idea. Seemed to be in a hurry, though.”
“Thanks.”
She coughed a little. Frowned when she felt the burn.
“Hey, Dr. Reeves, you hear anything about a student?” The woman scratched her head nervously. Her eyes kept darting to the angry red marks on Ivy’s throat.
“Student?”
“Yeah—a rumor’s going around that a student stabbed someone. Can you believe that?”
“No, no I can’t.” Deep down, Ivy knew she was lying, but it didn’t feel like one. Everything from the time that Zeke had gripped her throat to seeing Rebecca lying on her back, Vaughn’s fingers pressed to her skin, seemed like a terrible nightmare.
One that couldn’t possibly be real.
Ivy went outside. The PPD station was only a stone’s throw from Fine Hall, and Vaughn arrived in six minutes. Twenty-seven minutes . . . twenty-one remaining. Why twenty-seven? And why did that seem familiar?
Vaughn started to get out of his car, his face pinched.
“No, stay in.”
Ivy slid into the passenger seat.
“What the hell’s going on?”
Ivy produced the note and passed it to him.
“Found this in Dr. Moorehead’s office—the envelope had my name on it.”
“What the fuck . . .” Vaughn muttered. He turned to her. “You sure this is—”
“Look here: ‘sulfurous fate.’ That’s gotta be the gas, right? The hydrogen sulfide gas?”
“I guess. I still don’t—” Vaughn stiffened. “You think it might be your boss? Dr. Moorehead? Could he be behind this?”
Ivy blinked.
“I don’t . . . I don’t know. But I don’t want anyone else to die.”
“Why the hell is this note addressed to you?”
“I don’t know, Vaughn—maybe . . . maybe whoever is behind this figured out that I was helping you. These are GPS coordinates. I don’t know what the rest means, but I think we should go there. Now. We have twenty-one minutes left.” She checked her phone. Shook her head. “No—only twenty now.”
Vaughn nodded, kicked the car into drive while Ivy punched the GPS coordinates into the app on her phone.
“It’s the Basin—the Princeton Basin,” she said.
“The Basin?”
“Yeah—go.”
The coordinates didn’t lead precisely to the Princeton Basin, but to a forested area just on the eastern side of the Delaware Canal. On the opposite bank, a residential subdivision, but this specific bordered on an area that was mostly trees and trails.
The perfect spot for another one of those retrofitted barns.
Perfect . . .
8001.
27 minutes.
Add the missing number, reveal the site.
“If it was Zeke who set this up, everything could still be on a timer. The gas could still go off,” Vaughn mused out loud.
He was picking up speed as he spoke, but Ivy was barely registering his words.
Perfect . . . perfect . . . not quite perfect, but close to right.
8001.
Something clicked.
“But if it’s your boss who—”
“Do you have a pen?”
“Yeah, sure.”
Vaughn popped open the middle armrest, pulled out a pen.
Ivy saw a PPD pad of paper inside and took that, too. As she wrote, she heard Vaughn’s phone ring. Saw him click decline the call out of the corner of her eye. The phone immediately chimed again, and he cursed under his breath before declining that call, too.
Focus, Ivy.
“What’s going on?” Vaughn asked.
Ivy didn’t answer.
Twenty-seven was a prime number. All of the numbers from the 100 prisoners problem were prime. Hell, come to think of it, Joshua Perry and his opponent’s scores—twenty-three and seventeen—were prime numbers, as well.
But 8001 was not. Close, just like the poem said.
But the poem didn’t ask for a prime number. It wanted a perfect number. A number that was equal to the sum of all its proper divisors. The closest perfect number to 8001 was 8128. The difference between 8001 and 8128 was 127. 127 was also a divisor of 8128.
Ivy quickly scribbled numbers on the page to check her math.
1 + 2 + 4 + 8 + 16 + 32 + 64 + 127 + 254 + 508 + 1016 + 2032 + 4064 = 8128.
127 was missing . . .
Ivy referred to the poem again.
Add the missing number, reveal the site.
Ivy added 127 to the tails of both GPS coordinates. 40.3299 became 40.3426. -74.6637 became -74.6510.
She shook her head.
“It’s not the right address. It’s not the Basin.”
Ivy grabbed her phone, typed in the new coordinates. As she did, Vaughn’s phone rang for what seemed like the hundredth time. He finally answered.
“Delaney! We’ve got another attack,” he shouted. “We—”
“It’s the Thomas Clarke House!” Ivy interrupted.
“What the fuck is that?” Vaughn said out of the corner of his mouth.
“It’s in the Princeton Battlefield.”
“Where—”
Ivy shoved her phone toward Vaughn. She could hear Delaney saying something, but couldn’t make out the words. He squinted as he read her screen.
“You hear that, Delaney? Battlefield State Park. Get there, now!” Vaughn ended the call. To Ivy, he said, “I know it. Hold on.” He wrenched the wheel, started back toward Fine Hall, raced up Alexander Street.
“Hurry,” Ivy said.
They had thirteen minutes left.
Somewhere in the back of Ivy’s head she thought, Hey, that’s a prime number, too.