“Dr. Wallace, what happened to the sensory devices? We’re registering Dr. Liao’s device. Your unit appears to have been activated but isn’t tracking—”

“I lost it when I fell into a crevasse. Screw your damn instruments and get us to the extraction point before Ben bleeds to death.”

A moment’s pause. “I’m sorry for your loss, Dr. Wallace. I’m going to turn you over to Captain Eric Schager, whom I’ve instructed to pilot you out of that maze into the northern basin. We’ll have a medical team waiting for you back in the dome.”

“Thank you.” I laid my head back, then peeled off my gloves. Raising my dripping wet left boot, I attempted to unbuckle the straps with my half-frozen fingers.

“Dr. Wallace, this is Captain Schager. I’m tracking your position using our SAT feed, but there are going to be biologics along the way that I can’t see. I can take you safely out of the bay and back to the main river. After that it would be best if you piloted the sub under my direction.”

“I’ll do my best. But right now I can’t feel my feet.”

“Acknowledged. Coming to course zero-eight-four. Dive to sixty feet and proceed at ten knots. Call out if you see anything I should know about.”

Dark, frigid water washed against the acrylic dome as the Barracuda submerged and moved at a steady pace through a black sea.

Locating my night glasses, I worked them into place with numb fingers that began registering pins and needles of circulatory pain.

Blooming into view off our starboard bow was an albino elephant seal the size of a cement mixer.

Too tired to say anything, too exhausted to care, I barely gave it a glance as I held my hands to the hot air now pumping out of my console.

A powerful rush of current shook me awake. We had reentered the main river, its easterly flow sweeping us along at twenty knots.

I searched my snack stash and quickly consumed an apple and a bag of trail mix between two orange juices. My bladder signaled it was back on the job, and with a bit of aim and effort I managed to relieve myself in a plastic urinal.

“Dr. Wallace, are you ready to take over?”

“Two shakes.”

I took three, capped the bottle, rezipped, and adjusted my headphones. “Standing by, Captain.”

I felt the console’s joystick come to life in my right palm, the foot pedals responding beneath my throbbing, frostbitten feet. I had managed to peel off the climbing boots, but left my socks on, afraid of what lay beneath.

As instructed, I followed the main river, trekking east for several miles.

“Dr. Wallace, in half a kilometer you’ll come to a tributary off your portside bow. Follow that waterway; it flows into the north basin.”

“Acknowledged.”