The second leg went just as the insects tried again. This time, one of them dodged the billowing flames and got a grip on Isaac’s back. He bucked, trying to dislodge it, but it clung tenaciously. The spider groaned, six remaining legs splayed, but it had lost its balance. It started to tip, falling with the slow inevitability of a great tree coming down.

Oh, no. Isaac, fully occupied with the wasp, didn’t notice the collapse of the spider until it was too late. His claws scrabbled at its hide but couldn’t hold on, and he started to slip.

Alice moved fast. She hurled her flyswatter aside, splattering one last wasp, and pulled the Swarm thread around her. Her body dissolved into hundreds of tiny, rubbery swarmers, bouncing through the grass. A kaleidoscope of images whirled around her, the world as seen through hundreds of beady little eyes, but Alice was used to this by now. She kept herself together in a single pack, racing over the ground toward the collapsing spider, trying to gauge the distance.

Isaac lost his grip and fell. He was shifting back into a boy, but he didn’t have time for another transformation. He didn’t have anything like the Swarm, Alice knew, something to toughen his body or soften the landing. She pushed herself, tiny legs blurring, flowing around roots and rocks like a stream.

She got her tiny bodies underneath him just before he hit the ground. Isaac landed heavily on the swarmers and bounced back into the air, arms windmilling wildly, before landing again in the dirt a few feet away. Alice let the Swarm thread go, drawing herself back together, and found herself sitting in the grass. Her boots stood back by the wall where she’d left them. Try as she might, her transformations always left her footwear behind.

“Are you okay?” she said, hurrying over to Isaac in her socks. But he was already sitting up, rubbing his head.

“I think so.” He winced, and gingerly touched the top of his skull. “I’m going to have quite a bump, though.”

“Next time,” Alice said, “I’ll make sure to bind some sort of pillow-monster.”

Behind them, the mammoth spider hit the ground in a spray of dirt and grass.

The wasps had evidently decided they’d met their match, because they didn’t bother the two apprentices on their way back to the wall. Alice retrieved her boots as they went.

In the central hut, the huge flower had only one petal still closed, curled tightly at its very center.

“Thanks,” Isaac said. “Did I say thanks?”

“Several times,” Alice said.

“Sorry.”

“Look,” Alice said. “It’s opening.”

The last petal quivered, and with a slow sigh unrolled itself. The sweet scent of the flower filled the room. In the center of the mass of white-and-purple petals, six purple fruits, each about the size of an apple, hung from a long, drooping stem.