“Nearly a hundred feet at its deepest point,” Saxon said. “The lake is spring-fed.”

“Standard dive procedure is to plan the dive and dive the plan,” Zavala said. “It’s a big lake. Any idea where we should start?”

“I’ll show you,” Saxon said.

Back at the Suburban, Saxon extracted a file marked HOTEL GOLD STREAM from his bag and handed Zavala a yellowed brochure that touted the features of the hotel, shown as a two-story flagstone building.

A walkway led from the hotel to stairs that went down to the cave entrance, where the tour boats were lined up. A sketch showed people in Victorian attire panning sluiceways for gold. Zavala looked from the hotel layout to the lake, trying to visualize what lay under the surface.

“No one could find the mine when the hotel was high and dry,” he said. “What makes you think it will be any easier under water?”

“The same question occurred to me,” Saxon said. “I was about to call off the expedition when I came across a magazine article about the lost hotel. One of the former kitchen staff described a trapdoor in the kitchen. It had been locked, but the kitchen staff broke the lock and dropped something down to see how deep it was. No one could hear it hit bottom. The management put a stronger lock on the trapdoor because the kitchen people were dumping peelings down the shaft.”

Paul said. “The air shaft could have been dug to ventilate a mine.”

Saxon opened a sketch pad to a page where he had made a reasonable copy of the hotel from the tourist brochure. Double vertical lines marked the air shaft.

“I think the hotel was built over the mine,” he said. “The cave may have been part of the mine entrance before the ceiling caved in. The cave-in blocked access but not the flow of gold-laden water. If we go down that shaft, we can get into the mine. Do you think it’s doable?”

Zavala studied the drawing for a moment, going through each step of the dive in his mind. “Any idea how big the shaft opening was?” he asked Saxon.

“No dimensions were given in the article.”

Zavala was a careful diver. He proposed a two-stage plan. He and Gamay would explore the cave first, then check out the shaft. Gamay was a highly skilled diver who had explored many wrecks in the Great Lakes and, later, worked as a nautical archaeologist. With their slim builds, they might be able to navigate the shaft.

While Paul inflated a rubber raft, the divers got into their scuba gear. Saxon had charted out the hotel location on a topographical map enclosed in waterproof plastic.