“Ajay, what is this thing?” asked Karna.

“A Chetak light utility helicopter, sir. Very reliable. As a soldier, I flew in these many times.”

“How old?”

“Nineteen sixty-eight.”

“Bloody hell.”

“If I had told you, Mr. Karna, you would not have come.”

“Oh, you’re damned right. All right, all right, let’s get on with it.”

With Jack clawing furiously at his Nerf ball, the group packed their gear aboard, then took their seats. Ajay checked their fivepoint seat harnesses, then slid the door shut and gave the pilot a nod.

They lifted off, the nose tilted forward, and surged ahead.

Partially for ease of navigation and partially to increase their chances of rescue should the Chetak crash, the pilot followed the serpentine course of the Siang River. The few pockets of habitation that lay north of Yingkiong were situated along its banks, Ajay explained. With luck, someone would see the Chetak go down and report the incident.

“Oh, that’s just fantastic!’” Karna shouted over the rush of the engine.

“Squeeze your ball, Jack,” Remi replied. “Ajay, do you know this pilot?”

“Oh, yes, Mrs. Fargo, very well. We served together in the Army. Gupta now runs a cargo business-brings supplies to the far parts of Arunachal Pradesh.”

The Chetak continued north, skimming a few hundred feet above the brown waters of the Siang, and before long they found themselves flying through knife-edged ridges and plummeting valleys, all of it covered in jungle so thick Sam and Remi could see nothing but a solid carpet of green. In most places the Siang was wide and sluggish, but several times, as the Chetak passed through a gorge, the waters were a maelstrom of froth and crashing waves.

“Those are Class VI waters down there,” Sam called, staring out the window.

“That’s nothing,” Karna replied.

“Where we’re headed, the Tsangpo River Gorge, is known as the Everest of Rivers. There are sections of the Tsangpo that defy classification.”

Remi said, “Has anyone ever tried traversing those?”

“Oh, yes, a number of times. Mostly extreme kayakers, right, Ajay?”

Ajay nodded. “Many lives have been lost. Bodies never found.”

“They don’t wash downstream?” asked Sam.

“Bodies are usually either trapped forever in hydraulics, where they are ground into pulp along the bottom or they are ground into pulp while being dragged down the gorges. There is not much left to find after that.”

After they had traveled forty minutes, Gupta turned in his seat and called, “Coming up on Tuting Village. Prepare for landing.”

Sam and Remi were surprised to find that Tuting had a dirt airstrip partially overgrown with jungle. They touched down, and everyone climbed out. To the east, higher up the valley, they glimpsed a few roofs peeking above the treetops. Tuting Village, Sam and Remi assumed.

“From here, we hike,” Karna announced.

He, Sam, and Remi began unloading their gear.

“Pardon, just one moment,” Ajay said. He was standing ten feet away with the pilot. “Gupta has a proposal he wishes you to consider. He asked me how far into China we are going, and I told him. For a fee, he will fly us very close to our destination.”

“Isn’t he worried about the Chinese?” asked Sam.

“Very little. He says they maintain no radar in the area, and from here to our destination the valleys only deepen, and that there is almost no habitation. He can fly unseen, he believes.”

“Well, that’s a damned sight better than a six-day march in and back,” Karna observed. “How much does he want?”

Ajay spoke to Gupta in Hindi, then said, “Two hundred thousand rupees-or roughly four thousand U.S. dollars.”

Sam said, “We don’t have that much cash on us.”

“Gupta assumed this. He says he will happily take a credit card.”

They agreed to Gupta’s terms, and in short order the pilot was on the helicopter’s radio, transmitting Sam’s Visa information to his home base in Itanagar.

“This is surreal,” Sam said. “Standing here, in the back of beyond, while an Indian pilot runs our card.”

“As I said back in Nepal, never a dull moment,” Remi replied. “I know my ankle will appreciate this itinerary change.”

Ajay called, “Gupta says you are approved. We can lift off whenever you are ready.”

Airborne and heading north along the Siang again, they soon passed over the last Indian settlement before the border. Gengren disappeared behind them in a flash, and then Gupta announced, “We are crossing the McMahon Line.”

“That’s it,” Sam said. “We’ve invaded China.”

The crossing had been decidedly anticlimactic, but soon the landscape began to morph. As Gupta had predicted, the peaks and ridges traded their rounded appearance for exposed and serrated rock; the valley walls steepened and the forests thickened. The most startling difference was the Siang. Here, on the southern edge of the Tsangpo Gorge region, the river’s surface roiled, the waves exploding against boulders and hanging rock walls, sending plumes of mist high into the air. Gupta kept the Chetak as close to the river as possible, and kept below the ridgeline. Sam and Remi felt as though they were on the wildest flume ride on earth.

“Fifteen minutes,” Gupta called.

Sam and Remi shared an anticipatory smile. They’d come so far, gone through so much, and now their destination was only minutes away . . . they hoped.

Karna’s reaction was intense. Jaw clenched, fingers digging into the Nerf ball, he stared out the window with his forehead pressed against the glass.

“You okay, Jack?” Sam asked.

“Never better, mate. Almost there!”

“Approaching the outer edge of the coordinates,” Gupta announced.

Ajay had given their pilot a datum point with a two-mile diameter. The area into which they were flying was dominated by a cluster of flat-topped obelisk peaks, each one varying in height, from a few hundred feet to a thousand feet to three thousand feet. In the gorges below, the Tsangpo River twined itself around the obelisks, a churning white ribbon enclosed by sheer cliffs.

“Haven’t seen any kayakers,” Sam observed. “Or anyone, for that matter.”

Karna looked up from the map he was studying and replied, “I would be surprised if you did,” Karna replied. “You’ve seen the terrain. Only the most determined-or insane-venture here.”

“I can’t decide if that’s an insult or a compliment,” Remi whispered to Sam.

“If we make it back victorious and alive, it’s a compliment.”

Karna called to Ajay, “Ask Gupta if he can give us a better look at these peaks. If my numbers are correct, we’re right on top of the datum point.”

Ajay relayed the request. Gupta slowed the Chetak to thirty knots and began orbiting each of the obelisks in turn, adjusting his altitude so his passengers could make a closer examination. At her window, Remi had her camera shutter on rapid-fire.

“There!” Jack shouted, pointing.

A hundred yards beyond the window lay one of the medium-sized obelisks, at approximately a thousand feet high and five hundred yards wide. The vertical granite slopes were heavily laced with vines, foliage, and great swaths of moss.

“Do you see it?” Karna said, his index finger tracing along the glass. “The shape? Start at the bottom and go upward . . . Do you see where it begins to widen out and then, there, about a hundred feet below the plateau, it flares out suddenly? Tell me you see it!”

It took Sam and Remi several seconds to piece together the image, but slowly smiles spread over their faces.

“A giant mushroom,” Remi said.

TSANGPO RIVER GORGE, CHINA

After making several aborted passes because of wind shear, Gupta managed to ease the Chetak sideways over the obelisk until Karna spotted a small clearing in the jungle near the edge of the plateau. Gupta slowed to a hover and then touched down. Once the rotors had stopped spinning, the group climbed out and grabbed their gear.