“Is it some kind of fish?”

“Not a fish. But on the floor of the ocean are layers of something—perhaps a slime that is organized into larger structures.”

“But how would a slime make light?”

Ganymede clutched his black hair in his hands. “Light from slime is bioluminescence,” he said tightly. “Slime from light is photosynthesis. Both are very common. They’re like alchemical interactions.”

“But alchemy doesn’t really work.”

“Sometimes it does. Be quiet now. We have to get the Europans out of here.”

On the screen that had held the rainbow images of the flue, there stood now an image all in grays, in which near-white shapes defined an object much like their own vessel, shifting against a rumpled gray field. Ganymede took over at one desk and began to tap gently on the array of tabs and knobs. A solid bump, and then the screen showed nothing but the ghostly image of another ship. “Hold on,” Ganymede ordered grimly, and began tapping harder than ever. “Pauline, keep the vectors such that we push it up into its flue.”

Then a loud bang and instant deceleration knocked them all forward and up into the air. When they fell back, Galileo found himself in a heap of bodies in the corner, with Hera under him. He got up and tried to give her a hand, but staggered back as the vessel tipped again.

The voice named Pauline said, “They’re in their flue now, but they can descend out of it again.”

“Go after the other one anyway. Wait, while we’re in contact with them, speak hull to hull and tell them to get back to the surface. Tell them if they don’t, we’ll ram them hard enough to breach both ships. Tell them who we are and tell them I’ll do it.”

Suddenly a storm of blue flashes exploded in the window, and all the screens lit up as if with torn rainbows. The visual chaos was split by black lightning that somehow was just as devastating to the eyes as white lightning. Cries of alarm filled the air. Then the vessel lurched down and began to spin. Everyone had to hold on to something to stay upright. Galileo clutched Hera by the elbow, as high as his shoulder, and she held him up with that same arm while grasping a chair back with her other hand. One of the crew clutched her desk while pointing at her screen with the other hand. Ganymede moved like an acrobat across the bucking deck, inspecting one screen and then another. The officers shouted at him over a high ringing tone. On the screens, Galileo caught sight of a swirl of a steep conic spiral rising from the depths, now revealed to be immense—a matter of many miles. The blue light flashed in their chamber again.

“It doesn’t want us here,” Ganymede said. “Pauline, open radio contact with those ships. Send this: Get out! Get out! Get out!”

A high moan lofted up Galileo’s spine, leaving his short hairs as erect as a hedgehog’s. The sound resembled wolves howling at the moon. Often Galileo had heard them in the distance, late at night, when the rest of the world slept. But the sound filling him now was to wolves’ howls as wolves’ howls were to human speech—a sound so uncanny that actual wolves would surely have run away whimpering. Fear turned his bowels watery, and he saw all the others in the craft were just as afraid. He clutched Hera’s thick biceps, felt himself moaning involuntarily. It was too loud now for anyone to hear him; the super-lupine howls became a keening shriek that seemed everywhere at once, both inside and outside him. The blue flashes were now inside the vessel, even inside his eyes, though they were squeezed shut.

“Go!” Hera shouted. Galileo wondered if anyone else could hear her. In any case the vessel was spiraling upward now, so forcefully that Galileo was knocked to his knees. Hera swung him up and around the way he would have swung a child, and plopped him into a chair. She staggered, almost landed on him, then sat hard on the floor beside him. Black flashes still shot through them like lightning, through floor to ceiling, as if carrying them along in some stupendous explosion, aquatic but incorporeal, everything spiraling in a dizzying rise. It was like being in the grip of a living Archimedes screw. Up and up again, until there was an enormous crash, casting everyone up onto the ceiling, after which they flailed awkwardly down and thumped to the floor. They had struck the shell of ice capping the ocean, Galileo presumed, and it seemed the vessel might have cracked and everyone would soon drown. Then Galileo felt shoved toward the floor, indicating a new acceleration, as when rocked back on a bolting horse. The vessel itself now creaked and squealed, while the eerie shriek was muffled. The chamber was still bathed in flickers of blue fire. Ganymede, propped on both arms before the biggest table of screen and instruments, conferred in sharp tones with crew members holding on beside him. It seemed they were still trying to steer the thing.

Up they tumbled, turning and spinning this way and that, pitching and yawing but always moving up.

Ganymede said loudly, “Are the Europans ahead of us?”

“There’s no sign of them.” Pauline’s voice was small under the muffled shriek.

The shriek shot up the scale in a rising glissando, until it was no longer audible, but immediately a violent earache and headache assaulted Galileo. He shouted up at Ganymede. “Won’t we emerge too quickly, if we don’t slow down?”

Ganymede glanced at him, started tapping again on one of the desks.

Then the black on the screens turned blue, an indigo that lightened abruptly, and they shot up in a violent turquoise acceleration. Galileo’s head banged the floor of the vessel and he thrust an arm under Hera. The back of her head smacked his forearm, and it hurt, but she turned and saw he had saved her a knock.

On one screen splayed the starry black sky, under it the shattered white plain of Europa’s surface.

“We’re going to fall!”

But they didn’t. The column of water under them had fountained out of its hole and then quickly frozen in place, so that it stood there as ice, supporting their vessel just as certain sandstone columns held up schist boulders in an area of the Alps. Icicles broke and clattered away from the vessel’s sides, shattering on the low frozen waves now surrounding the column. Black sky, white ice, tinted the oranges of Jupiter; their vessel, like a roc’s egg on a plinth.

“How will we get down?” Galileo inquired in the sudden silence. His ears buzzed and hurt, and he could see crew members holding their heads.

“Something will come to us,” said Ganymede.

Hera laughed just a touch wildly, detached Galileo’s fingers from her arm. “The Europans will come for us. The council will come for us.”

“I don’t care, if they get the others too.”

“The others may have died inside.”

“So be it. We’ll tell the council what we did, and tell them they should have done it.” He turned to one of his crew. “Prepare the entan-gler to send Signor Galileo back.”

The crewman, one of the pilots, bustled out of the chamber through a low door. Ganymede turned to speak to another of them.

Hera leaned over and said quickly in Galileo’s ear, “They will give you an amnestic, and you won’t remember any of this. Drink salt water the moment you wake. Do your alchemists have magnesium sulfate? Well, shit—you won’t remember this either. Here—” she reached inside her tunic, pulled out a small tablet, gave it to him. “This is better than nothing. Hide it on you, and when you see it again, eat it!” She glared at him, her nose inches from his, and pinched his arm hard. “Eat this! Remember!”

“I’ll try,” Galileo promised, slipping the pill into his sleeve and feeling his arm throb.

Ganymede towered over him. “Come, signor. There is no time to lose, we will soon be apprehended. The other ships may not have made it, in which case good riddance to them, but we will have a lot of explaining to do. Let me convey you back to your home.”