Seth was leaning forward to untie the strap that bound the spadelike shovel when Richard screamed.

Seth lifted his gaze. Richard seemed to have shrunk. He had turned to face them, his arms outstretched for help.

“Help me!” Richard screamed desperately. Gunther shed his pack in an instant, fell on his belly, and began to crawl toward Richard, who had now shrunk to the size of a large stuffed bear.

It took Seth several moments before he realized that Richard had not shrunk at all, but had sunk into the floor of the tunnel. He flailed his arms and shrieked as he sank deeper and deeper. Around him, the hard-packed salt floor had turned dark with water. Condensation from the warm water formed a modest fog in the cool air of the corridor.

Gunther approached him cautiously now, his arms and legs spread to distribute his weight more evenly. There was no telling how far the floor had been undermined. Seth quickly shed his own pack and crawling on his belly moved forward to grab Gunther’s ankle.

Seth looked up. Only Richard’s head could be seen now. The man was grasping for Gunther’s outstretched hand. Pieces of the tunnel floor broke off around him and disappeared. Seth felt Gunther stretch out and grabbed the old Austrian. The next instant, Gunther shouted to Seth, “Pull! Pull us both. Now!”

Pulling with all his might, Seth edged backward, tugging against the grasp of the underground currents. Progress came by the inch.

“Here.” He felt strong arms pulling at his belt. Stratton had wedged his way around Morgen and Zoe to help.

They progressed a foot, a foot and a half, when the tunnel filled with a high-pitched scream. Seth and Stratton fell backward suddenly as the tension was abruptly released. Richard shrieked one last time, then disappeared into the wet sucking hole.

They sat there, too stunned to move. Zoe rushed to Seth and held him. Moments later, Gunther’s agonized weeping filled the air. Hans Morgen squeezed past to comfort him.

“It was not your fault, Gunther,” Morgen said, as he put an arm around his old friend’s shoulder.

“But I let him go,” Gunther protested. “I held him and I let him go.” He began to sob softly.

“You did all you could,” Morgen countered.

Seth, Zoe, and Stratton sat quietly for perhaps ten minutes before Stratton motioned them to follow him back toward the auditorium-sized chamber through which they had passed.

Gunther and Morgen were waiting for them when they returned, dragging two long boards the size of a two-by-twelve. Stratton and Seth jockeyed the boards into the narrow passageway while Zoe led Morgen and Gunther back to the stack of timbers they had separated from the pile of debris they had skirted on the way in.

It took them more than an hour, but when they finished, the hole in the floor of the passage was bridged with boards.

“We must hurry,” Gunther said. “Now that the water has broken through, we do not know how long it will take to eat away at the edges. It could swallow up our little bridge.”