Chapter 57

Inside Mauna Loa

Minutes after Rivers stepped away from the microphone without taking questions, Mac and Rebecca entered a lava tube on the southeast flank of the mountain.

Mac felt the same way he had for days: like there was a gun pointed at his head.

Mac and Rebecca each carried an LED flashlight as they advanced into the darkness underground. Mac hadn't even known this particular tube existed until Rick Ozaki discovered it the night before.

Rick and Jenny Kimura had come up here on their own because, they said, they were tired of staring at their screens. Rick had brought with him a gravimeter, which he used for surface detection because an empty tube read as lower density due to the absence of rock. After they returned and showed Mac what they had, Mac had pulled Jenny aside.

"It was your idea for you and Rick to go up there, wasn't it?" he asked.

"I just did what you would have done," she said.

"You're one in a million, you know that?"

Jenny smiled. "Just as long as you know," she'd said.

Now, about fifty yards into the tube, Rebecca Cruz asked, "Is it safe in there?"

"Define safe," Mac said.

"I was afraid you'd say something like that," she said.

The terrain was rough, nearly impassable in spots. They both stumbled and fell more than once. At one point, Rebecca made a startled noise as they felt the ground underneath them tilt; it was like the cave was being turned on its side.

"It happens like that sometimes," Mac said. "Nothing to worry about."

"Am I also not supposed to worry about how freaking hot it is in here?" she asked.

"I told you to dress light," Mac said. "Day at the beach." He shrugged. "So to speak."

As they walked deeper into the tube, Mac said, "This is all our way of trying to run an elaborate con on the lava. We want it to think it's going where it wants to go while we're actually making it go where we want it to go after those nifty bombs of yours are in place."

Rebecca said, "And we also want to keep it from going where we sure as hell don't want it to go."

"Near those canisters," Mac said. "And right through downtown Hilo."

She stopped and faced him. "You know, Dr. MacGregor," she said, "up till now you've only spoken to me in general terms about why we have to do everything humanly possible not to let the canisters blow."

The weird light was all around them; the beams of their flashlights reflected off the lava rock. The inside of the tube seemed like the quietest place on earth.

Mac finally said, "Is there a question here?"

"I'm asking if there could be some kind of explosion that would mean the end of life on this island," Rebecca said.

"Not just the island."

"So we need to get the placement of these bombs exactly right."

"And even if we do," Mac said, "we have no idea if they're going to work the way we want them to."

They were more focused than ever when they were back outside, sometimes making multiple measurements and calculations before they marked a spot. Mac stressed how important this area was, how they couldn't afford to make a single mistake.