The kids clambered out of the bookmobile with Mr. C and Pascal, Dr. Newton’s assistant, who had tagged along. They all stood in front of a gigantic building.

“Wow, I didn’t realize the Waksman Institute of Microbiology building was this huge,” declared Simon.

“And look,” Chelsea added, pointing. “There are all the geese, hanging around on the front lawn, just like Dr. Newton’s clue suggested.” Sure enough, there were hundreds of them, loitering about in the sunshine.

“Okay, so we’ve found the geese,” Jamal said. “Terrific. But I don’t know if we’ll find Dr. Newton here.”

Cooper spread his arms wide and laughed. “By the way, this should be called the macro, not micro, institute.”

When the group reached the entrance, Chelsea pointed at a plaque. “Hey, look. This is a national historic chemical landmark.

“That’s so cool. Science rocks!” Jamal said.

Maya put her hands on her hips. “So does history.”

“Come on, kids,” Mr. C said. “We have tracking to do. Let’s go inside and see if we can find any clues.”

The group looked around the small lobby.

“Now what?” Gabby wondered. “There’s not much here—just those posters over there.”

“Wait,” Chelsea said, “look at the pattern of the tiles on the walls. Maybe the number of each color contains the clue. I’ll count blue ones.”

“Green, green, I love green,” Maya sang. “I’ll count the green.”

“You’re wasting your time,” Gabby said. “Dr. Newton didn’t re-tile the wall while he was here in New Brunswick.”

“True,” Jamal nodded, “but maybe he used numbers that were already coded in the tiles as the clue.”

“Good point,” Maya replied, “we should finish counting.”

“If you want,” Simon said, “but I’m going to look around.” He walked over to the corner where the posters were. “Maybe the clue is on one of these.”

Soon, all the Trackers were calling out numbers and names on the posters, but none gave a clue as to where Dr. Newton might have wandered.