His current mission was no different. He didn’t think about hugging the wall of the passage so that the enemy couldn’t get behind him. He didn’t think about shouldering his rifle tight against his body, or the pain that it caused his injured shoulder. And he certainly didn’t think about what could be lurking in the shadows. Whatever it was, he would deal with it. He was a goddamned Marine.

The first hallway was clear, and, surprisingly, the glass door to Biome 2 was still sealed. With the power off he was forced to pry his way in. He shuddered as the rubber-tipped bottom of the doors squeaked, but within a few seconds he was in.

The glistening water of the pond filled his HUD with a green glow. It was the last thing he had expected to see. He had assumed the Organics were after the Biosphere’s water supply, but as another scream broke through the silence, he realized they were after something else—the team.

Kill the enemy and then take their resources.

It was one of history’s longest-standing military strategies, dating back to a time when humans were little more than hunters and gatherers. And now an alien life force that had traveled an unfathomable distance to reach Earth was using it against them.

Shocked into motion, Overton rushed out of the chamber and sprinted down the hallway. He didn’t bother looking in Biome 3. Out of his peripheral vision, he could see the glass was still in place. It was Biome 4 he was interested in.

He raced around a corner and eased to a halt as the mess hall came into view. The outlines of empty tables filled his HUD. There were no signs of life.

His instincts kicked in and he pushed on. Time was of the essence, and trumped any need to go undetected. He certainly didn’t like Timothy, but he wasn’t going to let another one of his people die. Besides, he knew if Owen and Holly were still alive, they would be close by.

The sound of Timothy’s screams broke through the silence again, and Overton blinked, enhancing his night vision. Judging by the strength of the screams, he put the man somewhere in the personnel quarters or the med ward. But without Alexia’s guidance, he had no way of knowing the exact location.

In the corner of his HUD, the mission clock blinked red, reminding him he had only fifteen minutes to meet his objective—anything longer than that would give the Organics even more of an advantage. His objectives were simple, yet complicated: rescue the survivors, get the power back on, and secure the entryways.

He slipped into the hallway leading to the personnel quarters, and his display glowed to life. With several blinks he enhanced the optics until he could see a powerful glow from the entrance to the med chamber.