I left it there, howling in the darkness, its cries of pain echoing through the ice tunnel. It was still crying out as I reached the hole in the crevasse.

I paused. Even though the animal had intended to kill me, it was clearly suffering.

How could I just leave it like this?

Easily, I told myself. If you climb back down to put it out of its misery, you’re using up precious energy. Think about William.

I did.

And that’s why I climbed back down.

The bear-dog seemed to sense that I was there to help. It laid its head down, panting in pain.

Trembling, I gripped the axe.

The first blow caused it to spasm.

The second ended its suffering.

The ice tunnel began to reverberate.

I leaped for the rope, a rush of adrenaline driving my arms and legs. I saw ice collapsing around me like a shattering mirror as I pulled myself out of the tunnel and up into the crevasse. Dragging myself to my feet, I swung the axe, burying its blood-covered spike into the rock overhead, climbing up the parallel walls with my boots.

I felt the tunnel collapse beneath me, swallowing the floor of the chasm. I cursed my foolishness, an insane act of kindness toward an animal that had been crippled as it had tried to eat me.

Managing my way out of the fissure, I hoisted my quivering body onto the snow-blanketed mountainslope. Shaking with exhaustion and spent nerves, I retraced my footprints to the remains of the rope and pulled myself up the steep incline through waist-deep snow until I was standing at the base of the mountain. Heading southeast, I set off at a quick pace, my feet numb beneath me.

I covered the distance so fast that I actually passed Ming’s sensory device. It was only after I came upon Ben’s spikeprints that I realized I had gone too far.

I was surprised to come across a second set of boot prints.

Ming? Why had she set off after Ben? Maybe she had been too scared to descend through the fog alone?

I followed the pair of footprints another thirty yards in search of return tracks, but found none.

That was a problem. If they had gone off together and still hadn’t returned, then something had happened to them.

They probably planted Ben’s device together, then found another way back to the sub after the crevasse opened up.

Wanting to believe that, I retraced my steps and descended into the fog bank.

I was fifty paces in, working through three feet of snow and near-zero visibility, when I caught a whiff of something that smelled like rotten eggs.

Sulfur?

I turned away from the scent, diverting down another path, a shortcut that brought me out of the fog. Below were the dark waters of the bay. As I began my descent, I saw the light.