“This is it,” says Roy quietly. “As deep as even Walt ever explored.”

The tunnel gusts and drips around them; the green fluorescents of the upper levels have surrendered to orange sodium floods. There’s no dust on the floor at all.

“What do you mean?” Michael shivers, and grips his coil of rope.

Roy’s looking at him strangely. “You don’t know?”

Michael frowns. “I know about the cryogenic malarkey, if that’s–”

“Walt didn’t dig these tunnels, he discovered them,” says Roy. “Everything above us is just a cover. Why else would he have built the Magic Kingdom in a swamp?”