Even with the drysuit on, when Astrid jumped into the water, the cold was like a kick in the chest. She couldn’t ever remember being that cold; even standing in the Antarctic night while Remie repaired the ice sensor. A minute later though she forgot the temperature as what seemed like a hundred penguins shot past her. They looked more like they were flying than swimming and soared along at incredible speed. Her eyes followed them and she saw more in the distance, along with a large dark patch in the water.

“That’s a bait ball,” said Dr. Feuillée’s voice over the radio. “It’s a huge cloud of krill. We’re going to swim over toward it. I want to remind you to be on your toes. There could be other creatures arriving to feed on the krill or the penguins and some of them can be dangerous. If you see something, report it, and then swim back toward the ship.”

They swam about a hundred meters until they could make out the enormous cloud of life, though it was only possible to identify it as krill by the few stragglers that swam closer to the humans. They proved to be the luckier members of their species, since the penguins left them alone, either because of their proximity to people, or the bird’s desire to scoop up more than one at a time.

“Keep a sharp lookout for orcas,” said one of the crewmen, Astrid couldn’t tell which one.

“I thought killer whales didn’t come in close to the ice,” said Christopher.

“That’s true in the arctic,” said Dr. Feuillée, “but down here we have a different and much larger population and they have taught each other to hunt far into the ice flows.”

“They aren’t dangerous to humans are they?” wondered Astrid.

“There’s no recorded case of an orca attacking a human in the wild. Still, they are powerful wild creatures and it is good not to take that for granted.”

Only a few seconds later, Astrid caught her first glimpse of an Antarctic mammal swimming underwater. It wasn’t a killer whale though, but a seal. It was about seven feet long, with fur that was almost white.

“Crabeater seals,” said Dr. Feuillée. “They don’t eat crabs though. They eat almost exclusively krill.

Soon there were dozens of lightly colored seals, pausing only briefly to eye the strangers before shooting into the cloud of krill. Then Astrid saw another seal. This one had to be at least ten feet long, with spotted fur, and was much heavier than the crabeaters. She recognized it as a Weddell Seal. She looked around but didn’t see any others like it.

“We have only about ten more minutes,” said Dr. Feuillée. “Lucas, Emma, and Enzo are going in with me for some closer shots. You kids stay back here with Hugo.”

The four researchers swam toward the feeding penguins and seals, lighting up the dark water with massive movie lights attached to the cameras. Astrid and the others did as directed but having nothing to do but watch the filming from a distance gave her time to remember just how cold she was. She was starting to feel a dull ache in her fingers and toes.

Suddenly a cloud passed over her. She looked up and for a second she thought the Weddell Seal had returned to give her a second look. Though it was about the same size and color, this was not the same seal. Instead of the friendly smile common to most pinnipeds, this creature had a mouth full of sharp teeth that would have put a Siberian tiger to shame.

“Leopard seal!” called Hugo, with a hint of panic in his voice.

Before anyone could do or say anything else, the sea mammal shot down toward them like a rocket. It opened its mouth and latched onto Astrid’s right foot, dragging her along like a big dog would drag a play-toy. Though she flailed her arms and kicked her feet, she was unable to get away, or even slow her descent, and the leopard seal dragged her down into the depths.

“Problème, Remie,” she said upon her return.

“Problem?” wondered Christopher. “What’s wrong?”

“One of the sensors isn’t working. It’s probably frozen. Maybe we can fix it. In any case, we’ll have to go out and get the reading on site.”

“All right,” said Remie. “Who’s going with me?”

“Christopher and I will go,” said Astrid.

Astrid and Christopher, bundled up to the fullest, climbed into the cab of the same large tractor in which they had been driven to the base the day before. They took their places behind the driver’s seat, now occupied by Remie. Nathan, down on the hanger floor, pushed the lever to open the great door and the tractor rolled out into the icy darkness.

It wasn’t snowing, but it seemed to be as the wind whipped tiny flakes of ice into the air in the beams of the ten great spotlights that led them through darkness. For the most part, the ice was smooth and the great tractor ground straight into the night.

“We’ll be there in just a few minutes,” said Remie. “This sensor is only four miles from the base.”

“It seems like a long way,” said Astrid, “especially if you were by yourself.”

“We’ve got the radio. If something happens to the tractor, we can call for help. Don’t worry.”

They had barely finished talking when they saw a blinking red light in the distance. Turning just a bit to the right, the Frenchman brought the vehicle to a stop right beside it. The light was atop a large blue box-shaped piece of equipment roughly the size of Astrid’s walk-in closet at home.

“It looks like the Tardis,” said Christopher.

“Yeah, it does,” agreed Astrid.

“This is just the control box. The sensors reach down through about 40 meters of ice and into the rock below.”

“Won’t the movement of the ice break them?” asked Astrid.

“Eventually, though the ice doesn’t move as much here as it does closer to the Ross Shelf.”

They left the tractor’s engine running and climbed out into the freezing air. Remie led them to the control box and opened a panel. He flipped several switches and then opened an interior door to check a row of circuit breakers. After flipping several of them, he pulled one out and replaced it from a small stack of them just inside the compartment. Once he did so, a bank of lights came on and he began closing the device back up.

“I can’t believe how cold it is,” said Christopher. “We’ve been out here seven minutes and I’m frozen through, even with all these layers of clothes. Look at this.” He pointed to the ice on the fur around his hood where the moisture from his breath had frozen.

“Makes you rethink global warming, eh?” asked Remie.

“Of course not,” he replied. “Humans add almost 30 gigatons of carbon to the atmosphere each year.”

“Good man. You’re right of course. Measurements of the ice here show that it is almost an inch thinner than last year. That may not sound like much, but it is year after year, and the change is increasing.”

“How can you put 30 billion tons of anything anywhere and not expect it to make an impact?” wondered Christopher. “Don’t you agree, Astrid?”

The girl inventor didn’t answer. Christopher turned to see her looking out into the frozen darkness.

“What’s up?”

“I was just thinking,” she said. “I wish I hadn’t watched The Thing.”