Nico shot a half look, trying to spy his brother and maintain his aim on his prisoners. A pungent smell of sulfur drifted into the bus. The bird took off flying crookedly as if it had lost its equilibrium. Without warning, Simon collapsed, sprawled spine first on the damp ground, the branch falling on top of him.
Cullen gaped. What had he just witnessed?
Nico’s mouth opened as he shouted for his brother.
“It can’t be,” Kit murmured.
“Can’t be what?” He darted attention between the fallen Simon and Nico, trying to understand what he was seeing.
Nico goggled, eyes wild as he tried to comprehend.
“Down!” Kit yelled as she ripped the bus into reverse and hit the gas, scrunching low. He grabbed for Tot as she slid around the floor. Nico fired a series of bullets shattering the windshield and spraying them with glass.
Cullen held Tot tight, struggling to keep them from being tossed about. Twenty frantic yards of full-speed retreat and Kit stomped the brakes, swung the bus into a turn. He managed to crawl into the seat, curl over the baby with one arm and hold on with the other. They were moving at top speed, the trees and bushes flashing by.
A risky glimpse told him Nico had run toward Simon but changed his mind and dove into his SUV instead.
Leaving his brother?
She passed the flooded parking lot by the trailers.
“Exit road,” Cullen said. “Maybe we can outrun him.”
“No,” she said frantically. “We need to go up.”
“Why?” he shouted over the squeal of tires, but she didn’t answer. Several steep routes spidered up and away from the trailer park. The first he spied was a twisting horse trail, a wooded hillside path with places where they could hide—which might be her plan—but it was rough and rutted. He grimaced as she rammed the gas and surged ahead. Would the bus be able to take the grade? Boots braced against the floorboards, he held steady as she zoomed up the hill.
The path was tight. The bus sprayed debris from its wheels as it struggled to keep traction. She swerved into a turn, then another. Why had she chosen this way?
There was no chance to ask her about it as they sped upward for one mile, then two. He’d lost sight of Nico. Behind them? Had he taken a different route? Gone back for Simon? When she finally guided the bus to a stop behind an enormous rock pile, overgrown with stringy bay bushes, he handed the baby over and grabbed his binoculars. “I’ll check.”
She triggered the door to open for him. He slipped out and climbed atop the rock pile to scan the routes leading up the slope to their position. He didn’t see Nico’s truck. He zoomed in on the lake, still uncertain about what he’d witnessed. What he saw there confirmed she hadn’t been overreacting.
He returned to the idling bus, and Tot lay against Kit’s shoulder watching a leaf on the windshield caught in a bullet hole, her fist wrapped in Kit’s hair.
“Didn’t spot Nico, but I could see the lake.” He hesitated.
She freed her hair from Tot’s tugging fingers and waited for him to continue.
“Simon’s ... still lying there. Looks dead.” His stomach felt queasy as he took Tot from her. “What happened, Kit?”
She chewed her lip. “I’m not sure.”
“Yes, you are. Explain it to me, please.”
She darted a look at the spinning leaf. “I think it was a limnic eruption.”
Tot grabbed for the binoculars hanging around his neck. He let her toy with the strap. “What’s that, exactly? I’ve never heard of a limnic eruption.”
“It happens when magma builds up under a lake and the carbon dioxide dissolves into the water until it becomes saturated. It’s like if you shake up a soda can. Some trigger pushes the gas upward, probably the volcanic activity, and there isn’t enough pressure to keep it in solution. It explodes and discharges the gas into the air.”
The gas. He stared at her. “Carbon dioxide causes suffocation.”
She nodded, resting her shaking hands on the wheel. “Yes.”
He reeled. Simon had suffocated, along with anything else in the vicinity that required oxygen. If Nico hadn’t put enough distance between himself and the lake, he might very well be dead also.
“And you drove up instead of down because carbon dioxide is heavier than air.”
