I turned my head with difficulty to study her. She was the oldest person I’d ever seen; her body was round and shapeless beneath her sack-like white dress, and her face was so seamed with lines and wrinkles that it was hard to make out her features. Her hair stuck up in a silvery halo that wafted gently in the cool air like an undersea plant. “Don’t try to move,” she said. “You’ve been through quite a lot, my dear.” The wrinkles around her mouth wriggled and shifted, and I realized she was smiling at me.

“What—who are you? Where am I?” I croaked, wincing as a whole new set of aches flared up in my body. In the cave’s light, I could see what a mess I was. My dress was torn and bloody where the Scarecrow’s harness had dug into my skin. My bare arms and legs were purpled with bruises and streaked with more blood. And every part of me hurt, from my scalp to the tips of my toes.

“You can call me Gert. Grandma Gert, if you like. But who I am and where you are can wait until you’ve healed. You’re dying, Jellia.”

“Dying?” I struggled to sit up and cried out as my broken body refused.

“Lie still.” Gert’s voice was gentle but firm. “What you’ve been through would have killed anyone without your power. Glinda’s machine—”

“You know about my power?” I wheezed.

“I said lie still, Jellia.” She scooped me up in her soft arms, so lightly that I barely felt the movement. It didn’t seem possible that someone so soft could be so strong. She waded into the pool with me still in her arms. “This may hurt a little, my dear.”

The clean, clear water of the pool rose around us. It was as warm as bathwater, but it felt thicker than ordinary water—almost like oil. Gert lowered me fully into the water and I felt it move against my skin insistently, almost as if it wanted something from me. I became more and more aware of the pain in my body—the pool was pulling it from me, bit by bit. I cried out in anguish and my open mouth filled with water; I swallowed involuntarily and felt a mouthful of the strange liquid move through my body as if it had a will of its own, worming its way through my veins.

I looked down at myself and saw that a thick, dark substance was seeping out of my pores, forming a black cloud around me that slowly dissipated in the pool. The pain in my body was slowly replaced with a warm, drowsy sense of bliss. Dimly, I felt Gert lift me up again and set me down gently at the pool’s edge. The bruises and blood were gone; my skin glowed, and my ruined dress had been replaced by a thick, soft white robe. Instead of feeling broken and exhausted, I felt refreshed.

“What was that?”

Gert was looking at me with an expression that was hard to read. It almost looked like pity. Though she’d just gone into the pool with me, her clothes were dry. “Magic,” she said.

“I figured that much out.”

She smiled. “It’s good to see you back to normal, Jellia. I must admit I was worried about you. We were aware you might encounter danger at Glinda’s, but we weren’t prepared for things to move so quickly. Come,” she said, offering me her hand and pulling me to my feet. “It’s time for some explanations.” But instead of continuing to talk, she took off at a brisk pace. I had no choice but to follow her as she led me away from the healing pool and down a bewildering series of tunnels, all lit by the same glowing phosphorescence that seeped out of the walls.

Sometimes the tunnels opened up into more caverns, each one of them full of marvels: a shimmering, underground meadow, radiating silver light and dotted here and there with towering wildflowers that rose into the darkness; another pool, this one so big I couldn’t make out its far side, where bright golden fish jumped and fell back into the water with a splash; a series of mysterious, enormous machines, which sent a shard of terror stabbing through me until I realized they were putting together elaborate clocks that slid past on a conveyor belt.

We were moving too fast for me to catch more than the briefest glimpse of each cavern before Gert dragged me along to the next tunnel. Finally, she stopped at a low wooden door, rapped sharply, and pushed it open without waiting for a response. I followed her into a smallish room, furnished with a huge black table and rough wooden chairs that took up most of the space. Three people sat at the table: a cloaked figure, a mean-looking old woman I didn’t recognize, and Nox, whose expression was distinctly worried.

“What are you doing here?” I asked him.

“He saved your life,” the cloaked figure said, and lowered her hood. I flung my hands up and took a step backward. Her perfect face, her heart-shaped mouth, her strawberry-blond curls—Nox hadn’t saved me, he’d betrayed me. Because the woman in front of me was Glinda.

Without realizing it, I’d backed up to Gert, who held me firmly in her fleshy arms. “It’s all right, Jellia,” she said, her soft tone doing nothing to slow my pounding heart. “It’s not her. I’d like you to meet Glamora—Glinda’s twin sister.”

I blinked and stared at the woman seated at the table. What Gert was saying made a kind of sense. This woman had Glinda’s face, but where Glinda’s eyes were like cold, hard chips of ice, hers were kindly. The set of her mouth was friendly, not cruel.

“Have a seat, Jellia,” Gert said, steering me to a chair. “We have much to discuss. And I imagine you’re hungry.” With that, she sat down next to me and snapped her fingers, her eyes twinkling. I was used to magic, but I was still taken aback by the feast that appeared on the table almost instantaneously—big platters piled high with fruit and cheese, fragrant loaves of steaming bread accompanied by creamy butter and honey, a huge tureen of some kind of soup that smelled like heaven. Gert handed me a plate and a gleaming silver fork that she plucked out of the air, and I helped myself.