Continued from Part Two.
Sarah and Melanie climbed the steps together, each holding a toddler in one hand and keeping the other hand on the guard rail. Jara trailed along behind them, relieved at not being the one who had to carry the children, but certain that they'd be dumped on her again when they reached the top of the building.
They went up the final set of steps -- bare concrete, and ending in a plain steel door which had been propped open with a cinder block. Jara caught a whiff of coffee as she stepped out into the sun, and blinked at the weight of the smell. She didn't really like coffee, but like everyone else she'd been drinking a lot of it lately. The alternative was too dangerous.
Sure enough, the professor - lean and wiry despite his gray hair - was hard at work on his machine. And, sure enough, he saw them emerge from the doorway and called, "Sarah, Melanie, I need your help."
Sarah came to her rescue. "Let Melanie watch the kids," she suggested. "Jara can help with this."
A rush of gratitude flowed over her as the professor nodded. Melanie looked surprised, but she took the toddler from Sarah's arms and went over to a corner of the roof, where the wall would offer the girls some shade. One of the twins started crying. Probably, Jara thought, she could smell the coffee and wanted another hit. Since the plague had struck, even the toddlers drank coffee.
"I'll be testing the pump," said the professor, raising his voice in order to be heard over the wind blowing across the rooftop. "Watch the line. If it leaks, we'll lose pressure..."
Jara nodded. The professor's machine was their only hope of salvation. If it didn't work, or if it lost pressure while they were using it, they were doomed.
The professor switched on the pump, and Jara watched one section of pipe while Sarah studied the other. She couldn't see any leaks; even a fine spray would have produced a visible rainbow. That was Evan's work, she thought admiringly. The professor might have designed the machine, but Evan was the one who knew how to put things together and make them stay. If he'd paid her even half the attention he'd paid this machine...
Maybe later, if we survive. Jara kept her attention on the machine. That was what mattered now. "It looks fine," she called, and heard Sarah echo her assessment.
"Excellent," said the professor, and powered down the pump. For a moment he slumped, looking exhausted. Then he grinned at them. "Can hyou get up ze ladder? Ve haff to put in ze grindinks."
It took Jara a moment to translate that. The professor tended to slip into a B-movie mad scientist accent when he wanted to put people at their ease, and it wasn't always easy to understand. Once she'd put everything together, though, she stepped onto the ladder and started climbing.
This was an older building, old enough to have a water tank on the rooftop. That was why they'd chosen it. The professor had built his machine around it, and now they needed to load it up so it could work. Sarah took a spot on the ladder just beneath her, and the professor started handing burlap bags up to them.
They were just starting to make progress when Evan and Doug stumbled out of the door and onto the rooftop. Evan turned and picked up the cinder block, while Doug slammed the door shut. A moment later they were wedging a makeshift wooden frame into place under the door knob, and setting the cinder block to hold it in place.
"Hurry," said the professor, and handed up another bag of coffee beans. "The infected are coming."