It seemed like only minutes before they zipped into a narrow bay. The water turned the consistency of shaved ice in blue sticky syrup. Arion came to a halt on a frozen turquoise slab.
A half a mile away stood Hubbard Glacier. Even Hazel, who’d seen glaciers before, couldn’t quite process what she was looking at. Purple snowcapped mountains marched off in either direction, with clouds floating around their middles like fluffy belts. In a massive valley between two of the largest peaks, a ragged wall of ice rose out of the sea, filling the entire gorge. The glacier was blue and white with streaks of black, so that it looked like a hedge of dirty snow left behind on a sidewalk after a snowplow had gone by, only four million times as large.
As soon as Arion stopped, Hazel felt the temperature drop. All that ice was sending off waves of cold, turning the bay into the world’s largest refrigerator. The eeriest thing was a sound like thunder that rolled across the water.
“What is that?” Frank gazed at the clouds above the glacier. “A storm?”
“No,” Hazel said. “Ice cracking and shifting. Millions of tons of ice.”
“You mean that thing is breaking up?” Frank asked.
As if on cue, a sheet of ice silently calved off the side of the glacier and crashed into the sea, spraying water and frozen shrapnel several stories high. A millisecond later the sound hit them—a BOOM almost as jarring as Arion hitting the sound barrier.
“We can’t get close to that thing!” Frank said.
“We have to,” Percy said. “The giant is at the top.”
Arion nickered.
“Jeez, Hazel,” Percy said, “tell your horse to watch his language.”
Hazel tried not to laugh. “What did he say?”
“With the cussing removed? He said he can get us to the top.”
Frank looked incredulous. “I thought the horse couldn’t fly!”
This time Arion whinnied so angrily, even Hazel could guess he was cursing.
“Dude,” Percy told the horse, “I’ve gotten suspended for saying less than that. Hazel, he promises you’ll see what he can do as soon as you give the word.”
“Um, hold on, then, you guys,” Hazel said nervously. “Arion, giddyup!”
Arion shot toward the glacier like a runaway rocket, barreling straight across the slush like he wanted to play chicken with the mountain of ice.
The air grew colder. The crackling of the ice grew louder. As Arion closed the distance, the glacier loomed so large, Hazel got vertigo just trying to take it all in. The side was riddled with crevices and caves, spiked with jagged ridges like ax blades. Pieces were constantly crumbling off—some no larger than snowballs, some the size of houses.
When they were about fifty yards from the base, a thunderclap rattled Hazel’s bones, and a curtain of ice that would have covered Camp Jupiter calved away and fell toward them.
“Look out!” Frank shouted, which seemed a little unnecessary to Hazel.
Arion was way ahead of him. In a burst of speed, he zigzagged through the debris, leaping over chunks of ice and clambering up the face of the glacier.
Percy and Frank both cussed like horses and held on desperately while Hazel wrapped her arms around Arion’s neck. Somehow, they managed not to fall off as Arion scaled the cliffs, jumping from foothold to foothold with impossible speed and agility. It was like falling down a mountain in reverse.
Then it was over. Arion stood proudly at the top of a ridge of ice that loomed over the void. The sea was now three hundred feet below them.
Arion whinnied a challenge that echoed off the mountains. Percy didn’t translate, but Hazel was pretty sure Arion was calling out to any other horses that might be in the bay: Beat that, ya punks!
Then he turned and ran inland across the top of the glacier, leaping a chasm fifty feet across.
“There!” Percy pointed.
The horse stopped. Ahead of them stood a frozen Roman camp like a giant-sized ghastly replica of Camp Jupiter. The trenches bristled with ice spikes. The snow-brick ramparts glared blinding white. Hanging from the guard towers, banners of frozen blue cloth shimmered in the arctic sun.
There was no sign of life. The gates stood wide open. No sentries walked the walls. Still, Hazel had an uneasy feeling in her gut. She remembered the cave in Resurrection Bay where she’d worked to raise Alcyoneus—the oppressive sense of malice and the constant boom, boom, boom, like Gaea’s heartbeat. This place felt similar, as if the earth were trying to wake up and consume everything—as if the mountains on either side wanted to crush them and the entire glacier to pieces.
Arion trotted skittishly.
“Frank,” Percy said, “how about we go on foot from here?”
Frank sighed with relief. “Thought you’d never ask.”