Contagious

Perry touched the st.i.tches on his lip as he thought. “Me and Bill probably watched football all day.”

“Where?”

Perry shrugged. “Probably just my apartment.”

“Naw, we know you were at a bar that night,” Dew said. His finger traced a line on his flat-panel screen. “Here we go. Where is Big Sammy’s Bar?”

“Westland,” Perry said. “Just about halfway between Ann Arbor and Detroit. Big screens, lots of hot girls.”

“That Sunday night you spent forty-six dollars even,” Dew said. “It’s on your credit-card history.”

Perry thought for a second, then nodded. “Yeah, sure. I do that with the tip, put in the right amount of change so it comes out even. Bill and I went to Big Sammy’s to watch the Lions play the Colts. The late game. They lost.”

“There’s a surprise,” Dew said.

“Come on,” Perry said. “Cut ’em some slack. They only lost by two touchdowns that time.”

“Then what happened?” Margaret said. “Game ended, what did you do?”

As he thought, Perry moved his finger from his st.i.tched lip to his black eye. “I went home. I think I was a little drunk, so I was driving real careful. No, wait, I got hungry so I stopped at a store to grab some munchies.”

“Where did you stop?”

Perry shrugged. “Man, I can’t say. That was like six weeks ago, and I was drunk.”

Dew leaned closer to the flat-panel. “Could it have been the Meijer grocery store, in Belleville?”

“Could be,” Perry said. “That’s on the way home.”

Margaret stood and walked over to stand behind Dew. “Why?” she said. “What’s significant about that particular store?”

Dew pointed to another line. His fingertip left a little smudge on the screen.

“Credit-card history shows Patricia DuMond bought over a hundred bucks’ worth of groceries at Meijer in Belleville,” Dew said. “At ten thirty-one P.M.”

Margaret sat back down in her chair and started pounding on the keys, excitement bleeding through to her fingertips. “That might give us something.”

Now Dew got up from his chair and stood behind Margaret. “So the vector is a grocery store?”

Margaret shook her head. “No, it’s probably not the store itself, or the food it sold. Otherwise we’d have certainly traced other hosts back to it.

But for the first time, we may have two hosts in the same location at the same

She typed a few keys, and the icon denoting Perry and Patricia’s infection slid west to hover over the Meijer store. The icon’s new location instantly created a visual curve, one that started in Whittaker, then moved gradually northeast through the two house icons near Rawsonville, then sharper east toward the Meijer in Belleville.

Perry had been there around 10:30 P.M. So had Patricia. If the hosts that lived in Rawsonville had been home at that time, which was likely...

“Clarence,” Margaret said, “can this thing call up historical weather patterns?”

“Probably,” he said. “Let me drive.”

Margaret stood and Clarence sat down.

Perry leaned over to watch Clarence’s hunt-and-peck typing. “You need a hand with that, champ?”

Clarence kept his eyes on the keyboard and the screen in front of him.

“I think I can swing it, chief, but thanks for being such a helper.”

“So it’s not the grocery store,” Dew said. “You think maybe something blowing through the air, right? Something airborne?”

“Airborne is a term for one host pa.s.sing the disease to another through sneezes, coughs or even breath,” Margaret said. “Look at the range on this curve. We’re talking miles here, not feet. The more accurate term is wind-borne, where wind is the mechanical vector driving the spore.”

“But wouldn’t Cheng have checked weather patterns?” Dew asked.

“Of course,” Margaret said. “But the wind can change direction from minute to minute. We now potentially have an exact time of infection. Cheng never had that. Perry, what did you do after you got your food?”

“Ate it on the way home,” Perry said. “Got home, got undressed and went right to bed. I had work the next day.”

“The vector must have been on your hands,” Margaret said. “Or maybe on your clothes, and when you got undressed you spread it around. You must have touched... uh... some private places.”

“A guy scratching his b.a.l.l.s in the privacy of his own home,” Dew said. “Imagine that.”

“Okay,” Clarence said. “I have historical weather. What do you want, Margo?”

“Give us wind direction at ten thirty P.M. Sunday,” she said. “Focus in on Belleville if you can.”

Otto tapped away. Blue arrows appeared, pointing mostly east and a little bit north. A green line of text at the bottom read.5 MPH, 260 DEGREES.

“That doesn’t work,” Dew said. “The wind direction doesn’t line up the Rawsonville hosts with the store.”

“Clarence,” Margaret said, “show me a time-lapse projection of wind patterns from ten P.M. to ten thirty P.M.”

Otto looked at the keys for a second but didn’t type. “Uh... I don’t think this computer can do that.”

“Jesus H,” Perry said. “Give me that.”

He grabbed the keyboard and pulled it onto his lap. His big fingers flew across the keys. Data fields popped up on the screen and filled with strings of text faster than Margaret could even read them.

“You people remind me of the idiots I used to support at my job,” Perry said. “It’s like you’ve never read a software manual in your life. This is basic stuff, guys.”

He hit one last key, and the blue arrows on the screen changed. Instead of a west-to-east orientation, they started pointing north, then curved northeast, and finally wound up pointing due east.

Perry clacked a few more keys. The blue arrows vanished save for one—an arrow that started at the Whittaker house’s icon, curved to the right to cross over both the Rawsonville icons, and then farther to the right to cross over Meijer’s.