“Are you ready?” Cera asked.
Ursula swallowed hard, trying to steel her nerves. This was it. Once in the air, there would be no turning back. They were heading right for the Lacus Mortis. And while her Latin knowledge wasn’t spectacular, she had a feeling that name translated to, “the place where you’re about to die.”
“I guess I’m ready.”
Cera whispered in Sotz’s ear, and the bat climbed over the railing. “Hold on tight,” Cera shouted.
An instant later, the cold lunar wind whipped over Ursula’s skin, and they were diving toward the valley floor. With her hair fastened behind her head, the improved view proved so terrifying that she shut her eyes anyway. She opened them only when Sotz leveled off.
“Are you okay?” Cera shouted above the wind.
“Yeah.” And by “yeah,” I mean I’m so terrified I might puke into the wind. “Is it strictly necessary for Sotz to dive like a maniac every time we take off?”
“It’s the easiest way for him to build up enough speed to sustain flight. A bat’s not really built to take two riders.”
Her stomach twisted. Brilliant. Perfectly reassuring.
Sotz flew in a lazy curve until they faced the wall of the crater. The frigid air bit at her skin, even through her leather. Still, now that they weren’t hurtling at the ground, her muscles began to relax.
Sotz slowly beat the air with his wings a few times. Then he dove toward the side of the crater. They were heading for a sheer cliff of lunar rock at a terrifying speed.
Ursula gripped onto the saddle so tightly she was about to rip the handles off. “What are you doing?” she shouted. “We’re about to crash into the side of the crater!”
A moment later, in conjunction with Ursula’s terrified screams, they plunged into a narrow crack in the side of the cliff. Sotz had taken them into complete darkness.
Ursula strained to see anything, total darkness enshrouded them. Unlike the subway, no lights hung to illuminate their flight. If she’d had the nerve to release her grip for a second, she wouldn’t have been able to see her own hand in front of her face.
“Where are we going?” she shouted.
“Can you be quiet?” Cera barked. “All your shouting will interfere with Sotz’s echolocation.”
Right. Best not deafen the bat. Ursula tried to peer into the darkness for a few more moments, but she kept imagining stalactites dangling from the ceiling and smacking her in the face. So she shut her eyes and buried her face in Cera’s back.
The air rushed around her, but the sensation of Cera’s soft sweater against her cheek made her feel secure. After a while, the air around her seemed to warm.
Ursula lifted her head, opening her eyes. A dim, indigo light shone through the crack. Sotz’s wings beat steadily. The light slowly grew brighter.
Suddenly, the tunnel widened and they burst into an enormous cavern. A tremendous cacophony of chirping and squeaking assaulted her ears, echoing off the cavern walls. It sounded like a tropical rainforest amplified through a speaker. Down here, the humid air warmed her skin. She breathed in, taking in the sharp, almost chemical scent. It took her a moment to identify it—ammonia.
A luminous glow rose from beneath them. Ursula leaned just far enough to the side to peer over Sotz’s side. She gasped. They were flying over a great forest of glowing mushrooms. Enormous fungi, the size of trees, grew from the surface. Each glowed with a blinding cornflower-blue light. And between the fungi, something slithered.
Her stomach fluttered as she realized what they were. Monstrous caterpillars, the size of buses.
“What is this place?” she whispered.
“This is the rookery, for the bats.” Cera pointed above. “Look. You can see them up there.”
Ursula craned her neck, peering into the darkness. On the ceiling hundreds of feet above, furry bat bodies squirmed like a brown fungus.
Suddenly, Sotz jerked to the side. Out of the corner of her eye, Ursula saw a blur of brown plunge from the ceiling. It struck a mushroom with an audible splat.
“What was that?”
“Guano,” said Cera. “The bats aren’t exactly polite.”
Ursula’s stomach turned. Lovely.
As they continued through the cavern, Sotz continued to dodge falling guano.
“This is gross,” Ursula muttered.
“The guano feeds the mushrooms,” said Cera. “It’s a well-functioning ecosystem.”
Eventually the walls narrowed, and the ceiling sloped lower. As the sounds of the bats faded, the cavern grew dark again.