Eliot had said Umber was under the swamp, which was both very specific and very vague. She thought about just jumping in blind, a leap of faith in Eliot and his intelligence-gathering skills. But then, giant turtle. While she was weighing the options, Poppy passed her and began climbing down the ladder. It was a slight breach of discipline, but this once she was going to let it pass. Poppy dipped an elegant toe in the water, then put her whole foot in.

“Huh,” she said.

“Careful.”

Poppy wasn’t careful. With the traditional Australian’s indifference to personal dryness and venomous underwater predators, she dived right in. The bog swallowed her up in one gulp, her entire lean length.

“Poppy!” Josh peered down after his vanished wife-and-child. “Poppy! Jesus!”

Nothing. Then Poppy’s hand broke the still surface of the water, like the Lady of the Lake, except in this case instead of offering up a magic sword the hand just delivered a big enthusiastic thumbs-up.

“Oh, thank God.”

Josh executed a well-practiced cannonball off the dock. Bombs away. So much for stealth. Janet descended the worn wooden ladder in a dignified fashion, like a normal person, until she was immersed up to her knees. She saw what Poppy meant—it did feel weird under there. Not wet, somehow, and like there was something trying to push her back up and out. She leaned down and put her head under.

And collapsed in an upside-down heap on wet ground. Janet felt thoroughly nauseated; her inner ear was objecting strenuously to what it was hearing from the rest of her senses. Something violently disorienting had just happened.

“Jesus!” She spat to keep herself from throwing up. Josh was already on his feet and jumping up and down.

“Again! Again!”

At least somebody was enjoying themselves.

They were under the water, the three of them, but inverted; that’s what had happened. They were standing on the underside of the surface of the swamp, which now was hard and slick. It was dark down here, but it was pretty clear what the main event was, namely a big castle that looked exactly like Whitespire but creepier, its battlements all lit up with flaring white torches. The sky above it—or the lake bed, or whatever it was—was black.

“An underwater, upside-down Castle Whitespire,” Josh said. “I’ll admit, that would not have been my first guess.”

“It’s a mirror image.”

“Mirrors invert left-right, not up-down,” Poppy said, with tedious correctness. “Plus the black-white thing isn’t—”

“OK, OK, I get it.”

They met no resistance, but the drawbridge was up, so the three of them flew over the wall and into the courtyard. They saw no one. Josh knocked on the thick door to the outer hall. No answer, but it opened easily. The place looked empty but not abandoned—it was neat and clean, and more torches smoked and sputtered along the walls.

“Spooky,” Poppy said.