Once the snail was listed, the Aleys showed that an endangered species does not have to hurt a landowner. In their hands, it became a bonanza. Tom persuaded government agencies to hire him at his usual rate of $110 an hour to refine the watershed delineation, study neighbors' septic systems, and assess snail threats from activities like the repaving of nearby roads. The Nature Conservancy gave the Aleys $15,000 to build a new septic system for their lab and house. The Missouri Department of Conservation funded a $25,000 gate at the cave's natural entrance that lets in bats but keeps out humans, which is reputed to be the largest of its kind in the world. So the Aleys could lease one old farm to a neighbor for cattle grazing but exclude livestock from sensitive drainages, the Missouri Conservation Heritage Foundation gave $25,000 to buy a conservation easement, relocate a well, and put up fencing. To inventory and clean out the dozens of garbage dumps on the Aleys' newly acquired lands, the National Park Service and USFWS gave $40,000. Members of regional caving clubs volunteered hundreds of hours of labor. They helped haul out 100 tons of scrap steel along with containers of pesticides, drums of paint and waste oil, roofing material, washing machines, plastic toys, and enough Pampers to diaper a small nation. For Afghanistan, the USDA paid $175,000 to install fencing that would keep out livestock, regrade and replant eroded gullies, and plant 70,000 native trees. Under its soil-conservation program, the department also in effect rented the land, paying the Aleys $112,500 over 15 years in return for protecting the watershed. In all, Aley estimates the snail has brought in more than $500,000 so far. "Tom's our poster child for educating people who think endangered species will take over their properties," says McKenzie.

Some locals appeared jealous. Rumors swirled that the money for the land came from an illegal still, a marijuana plantation, or a methamphetamine lab, each supposedly hidden in Tumbling Creek Cave. Some said the Aleys were fronts for a government plot to take over Taney County for a nuclear-waste dump. Others questioned whether the snail really existed -- or, if it did, how the Aleys got this government largesse while everyone else was poor. The Aleys are unapologetic. Sure, they've made money on government grants; so have their employees, who are paid to carry out some of the government-funded projects. The Aleys also own the government-funded improvements to their lands, such as fencing -- and obviously the properties have grown in value now that they have been rehabilitated. Moreover, the price of land in the area is generally rising, thanks to the proximity of Branson and other resort developments.

Still, says Aley, "Some people don't get it. This is not for profit. My kids will not be burdened by personal wealth." The Aleys' land and retirement funds have been willed to their newly founded Tumbling Creek Cave Foundation. The core area around the cave has already been transferred. "We don't go on vacations. I don't go to the hair-dresser or buy jewelry. All we do is work to protect the cave," says Cathy. "I have no desire to own 2,650 acres. I look around and it frightens me how much work there is to do."

One day I visited the area's only public building: Mark Twain School, a shoestring operation with 60-some students from pre-school to eighth grade. The principal is an ex-Marine named Dick Needham. In late 2003, said Needham, Aley told him that the school's leaky open-sewage lagoon was polluting the cave. Around the same time, state health inspectors told Needham the lagoon had to be replaced, cave or no cave. The cost: $90,000. Needham feared Mark Twain would be forced to close and vigilantes would come for the head of Tom Aley, whether Aley was to blame or not. "Dick, the snail can be a friend, not an enemy," Aley told him. He was right: State conservation and USFWS officials facilitated a meeting at which federal, state, and local agencies cobbled together grants totaling $89,000. This included $2,000 from the Aleys themselves. A new septic system was completed in March 2006. "That snail was our salvation," Needham told me. As we walked over the still dug-up ground, he said he tried to change the school's mascot from the Pirates to the Cavesnails. "The school board wouldn't go that far," he said, "but attitudes here have definitely changed."

One afternoon Tom Aley and I drove to the edge of Afghanistan. Rolling into the distance nearly to the horizon, its hills and valleys are now grassy, and new trees sprout. But unfortunately, the recovery of Tumbling Creek itself is still in question. Due perhaps to the new gate, bats have roared back. Tumbling Creek is clearer, but sediment in the streambed will take a long time to clear completely. There are still no more than 150 snails, all in a stoopway that requires crawling several dozen feet through an icy stream to reach. The Aleys are now testing an apparatus designed by a mollusk expert to raise snails for reintroduction into the cave. It may take 20 years for the snails to return, if they do.

"Probably a lot of things that live in the cave have been reduced, but we don't have the studies to prove it," said Cathy. "The snail gets all the attention."

In the latest threat, feral hogs have been released by would-be hunters, and they are rooting up the woods, eroding soil all over again. Branson is still metastasizing. The Aleys have their eyes on 1,000 more acres to protect the cave, but for that they need $1 million, and they are both getting arthritic and gray.

One day they sent a young assistant into the snails' side passage to retrieve a few specimens for photographs. "I'd do it, but my knees are boogered up, and these days, those tight spaces seem tighter," Aley said. "And funny thing -- those little cave critters look littler all the time. At least to my eyes."

We stood in the darkness. I did not want to ask the obvious, but I made myself do it. "So," I said, "do you think you'll live long enough to see Tumbling Creek recover?"

Aley let out something between a chuckle and a snort. "Damn right," he growled.