“I’m not going to make it? What does that mean—you’d leave me here? Shoot me in the leg, is that it? You’re going to try to cast me off so you have more food and water for yourselves. I’ll tell you something, it won’t be me that dies next.” Dr. Silex’s stare was that of a man unhinged and dangerous. Alex put his hand on Silex’s shoulder, turning him round so he could bring his face very close to the scientist’s so that only he could hear. “Dr. Silex, my job is to keep you all safe. But if you look to endanger the rest of us, then I will no longer regard you as part of the group and my protection duties for you will cease. Do you understand me, sir?”

Silex spun out of Alex’s grasp and briefly turned to hiss something inaudible, then retreated to the back of the cave. As Alex watched him go, a small flame burned within him. He closed his eyes for a few seconds and pictured a golden beach with sparkling water and crashing blue waves—it all seemed a lifetime ago.

Several miles out on the black sea the water lumped as something large broke the surface. It stayed there for a few minutes, hanging in the water, its enormous body supported by fluid-filled sacs providing neutral buoyancy at any depth it chose. It had sensed the blood trail and felt the compression waves from the explosion. It could not yet detect the source of the scent but could sense movement on the water’s edge. The opportunity to feed close to its home and not have to hunt in the upper caves was too attractive; it slid silently below the surface and propelled itself swiftly towards the beach.

After scanning the surrounding walls for several minutes, Alex called the group together. Silex refused to join them and sat at the back of the small cave, watching the team from under his lowered brows.

“OK, there are multiple caves all around us—one or more must lead back to the surface. I figure we don’t have too many opportunities to make a wrong choice and double back. So, how do we narrow our search and make a higher value choice the first time?”

Monica was the first to respond. “Should be simple really; there are two indicators we can use. The first is change in temperature. The further we descended the warmer it became. Therefore, we should choose a cave that seems cooler than the rest, signalling that it leads to more topside Antarctic surface temperatures. The second, unfortunately, runs counter to the first. Warm air rises. We need to find a vent that is channelling warm air to colder temperatures. It will be like a wind tunnel. If the wind is strong, this will mask any colder air we could detect at this level.”