The boat captains in Seward had warned her it was three hundred nautical miles to the Hubbard Glacier, a hard, dangerous journey, but Arion had no trouble. He raced over the water at the speed of sound, heating the air around them so that Hazel didn’t even feel the cold. On foot, she never would have felt so brave. On horseback, she couldn’t wait to charge into battle.
Frank and Percy didn’t look so happy. When Hazel glanced back, their teeth were clenched and their eyeballs were bouncing around in their heads. Frank’s cheeks jiggled from the g-force. Percy sat in back, hanging on tight, desperately trying not to slip off the horse’s rear. Hazel hoped that didn’t happen. The way Arion was moving, she might not notice he was gone for fifty or sixty miles.
They raced through icy straits, past blue fjords and cliffs with waterfalls spilling into the sea. Arion jumped over a breaching humpback whale and kept galloping, startling a pack of seals off an iceberg.
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.

The Son of Neptune, Chapter XLIII