A Soviet submarine’s precise directives were never known to its captain upon departure, but Kobzar and his crew knew the broader plan: to follow a prescribed course to K-129’s station, a relatively small block of ocean well to the northwest of Hawaii, and more or less sit there—in a remote section of the Pacific, infamous for heaving seas and flotillas of flotsam and for being largely barren of nautical activity except for the silent passage of American hunter-killer subs that stalked Soviet ballistic missile subs. The K-129’s mission was to stay out of sight of these subs, or any other hostile American vessels, until returning to base on May 5 at no later than 1200 hours.

The sub slipped out of her bay, docked briefly alongside a floating barracks ship, then cruised on to the fleet weapons depot to pick up the ballistic missiles and nuclear-tipped torpedoes. Once loaded, the K-129 moved farther into the bay and anchored, to await the arrival of a large antisubmarine ship that escorted her as far as the booms, a standard procedure meant to signal loud and clear to any Americans watching that the sub leaving port was on a combat mission, carrying live nukes.

At twelve fifteen a.m. on February 25, the submarine passed the booms and headed into the open ocean. At one a.m., a monitoring station picked up a signal that the K-129 had submerged, and then it went quiet. After leaving Russian waters, the sub headed south until it reached 40 degrees latitude, then turned toward Japan, under orders to spend at least 90 percent of her time submerged, mostly at a depth of around one hundred feet, running on underwater diesel power (UDP). This was a hybrid stealth mode mandated by fleet command to keep Soviet subs hidden yet still within range of radio signals from shore. It was a far more risky (and noisy) position than cruising under battery power at a deeper and safer depth, but Soviet sub captains were under orders to operate according to UDP protocols as much as possible—and a mission’s success was in part judged by the percentage of time spent in this mode.

The K-129 cruised more or less in a straight line, with periodic zigs and zags to seek out and shake any American subs that might be trailing. Submarine warfare during the Cold War was a game of hide-and-seek. All captains of slower ballistic subs considered their vessels prey for attack subs and were trained to move evasively, making unpredictable course changes regularly. A sub might ascend or descend suddenly and would occasionally shut down all engines so the crew could just sit silently and listen for any external sounds that would indicate American hunter-killers lurking nearby.

At 180 degrees longitude, the K-129 was to turn again, toward the US coast. To prevent detection, especially considering the rising geopolitical tensions in the region, the K-129 traveled for two weeks in silent mode, running on battery power. As far as anyone back at command was concerned, she was proceeding as directed.

Vulnerable at snorkel depth, diesel-powered boats routinely and unavoidably traveled there. Golfs were the last generation of Soviet subs to have diesel power (all later generations had nuclear power, which eliminated the necessity to surface), and those noisy engines cranked up when a sub surfaced to charge the electric batteries that made cruising silently underwater possible. Ascend, charge, submerge. The pattern repeats over and over.

Inside, there was no fresh air. The caustic, bitter smell of diesel fuel permeated every inch of the submarine, seeping into clothes, mattresses, and sheets. And there was little freshwater. Each crewman was allowed a single liter per day, and that had to cover drinking, bathing, and—very occasionally—laundry. The entire crew shared three toilets and slept in bunks stacked so tightly that there was barely room for a man to lift his head.

When a sub is on or near the surface, all personnel stand at the ready, with key officers manning the boat’s two periscopes: the sky-search scope, which points straight up to spot sub-hunter planes; and the attack scope, which scans the ocean surface in search of foreign vessels. At prearranged times, the K-129 would also use these opportunities to send word back to Kamchatka, in the form of encoded burst communications that told superiors back at base that the mission was continuing as planned and that no problems had arisen en route.

A submarine’s most important attribute is stealth, and what made subs so important during the Cold War was that they enabled both sides to move nuclear missiles from land—where their fixed positions were easily located and, in theory, destroyed if a war were to break out—to sea, where on these silent, mobile launch platforms they would remain capable of striking and prolonging a war even if the homeland’s nuclear arsenal had been eliminated. Locating Soviet subs, then, was a huge priority for the US Navy, which had an almost unlimited budget for intelligence and antisubmarine warfare tactics—a line item so important that it required no congressional oversight.

The Soviets were aware that any radio transmissions sent between the subs and the mainland were intercepted by a network of land-based installations. What frustrated US Naval Intelligence was that analysts could not unlock these communications—typically short bursts of code sent at prearranged times and from specific locations—so while they could hear when and from where a particular burst originated, analysts had no idea what specific information was being transmitted.

Like any Soviet captain, Kobzar did not learn his official orders until the sub was in the open ocean. They were contained in a packet handed to him by his commander just before departure. The envelope was marked with clear directions: “To be opened on the third day after leaving base.” Kobzar bore a heavy burden—he was in a position to start a war if necessary, and should that happen, he would be asked to target and destroy three of the most critical US military installations in the Pacific: Pearl Harbor, Hickam Air Force Base, and US Pacific Command Headquarters, in Oahu.

Nothing about this was new, and there was nothing new about the mission either. It was a routine combat patrol, hopefully doing very little. Only in the event of combat was Kobzar allowed to think freely and react, and even then, very specific instructions for handling himself and the precious ballistic load on board had been drilled into his head.

Pacific Fleet command expected to hear from all deployed subs at prearranged times, but the K-129 was to travel in silent mode for the first two weeks at sea, so until March 8, there was no reason for anyone back in Kamchatka to worry. On the eighth, however, a watch officer at Soviet Navy Central Command noticed that the sub failed to transmit a radio message as scheduled, and he brought the matter to his superiors. An alert was declared.

Rear Admiral Dygalo was at the home of one of his captains that night when the phone rang at ten o’clock. It was the squadron commander, who wanted to see Dygalo immediately. A quarter of an hour later, he arrived at headquarters to find Krivoruchko pacing frantically while smoking a cigarette as if he were in a race to finish it. His previous cigarette was still smoking in an ashtray.

There has been no communication from the K-129, Krivoruchko said. The fleet commander was already on a plane from Moscow and would be at headquarters in the morning expecting a full report with explanations for the apparent disappearance of a submarine carrying ninety-eight men and three ballistic nuclear missiles.

“When ready, report to me on the possible reasons for Kobzar’s silence, and on the forces necessary for the search operation,” Krivoruchko told Dygalo.

A failure to communicate didn’t necessarily indicate disaster. Radio transmitters are not infallible, and Soviet submarines were notorious for equipment failure. Weather can also be an issue. And if a sub’s commander felt his boat was under threat of discovery or attack by American vessels, he might also choose to remain silent. Thus, Soviet admirals didn’t automatically assume the worst when a sub failed to communicate. But it was rare for one to go completely dark for more than a full day, and when the K-129 missed a scheduled communication for the second consecutive day, fleet command began to panic.

Although the Soviet Union had never lost a submarine with nuclear missiles on board, the idea of it happening was a nightmare for command. The crew of officers that Dygalo assembled offered a number of possibilities for the silence—damage to the ship’s antennas, a collision with another vessel, a sudden loss of buoyancy caused by a leak or massive water intake through the snorkel while under diesel power, or a catastrophic fire caused by a leak of rocket fuel or oxidizer from the ballistic missiles. In some rare cases, they noted, freakish ocean conditions—a zone of higher-temperature or low-salinity ocean water, or a run-in with subsurface waves—can even push a sub suddenly toward its depth limit, the point at which its hull collapses.

Dygalo recalled one such rare case. In March 1965, the sub K-163 was on patrol in the North Pacific when, in less than two minutes, it plummeted from forty meters nearly to its crush depth—the point at which the integrity of its steel hull is compromised—and was saved only because the watch officer noticed the change immediately and ordered the engine room to go full power toward the surface. This slowed but did not stop the sub’s plunge, and it kept descending right up to the precipice of its crush depth again, when the sub, its steel hull groaning violently from the ever-growing water pressure, finally stabilized and began to rise.

There were plans for rescuing vessels in distress, and the Soviet Navy put them into effect on March 9, dispatching a flotilla of ships, from various ports, out to sea. A damaged submarine will always surface, if possible, so the fleet’s reflex is to commence a rapid search for a crippled sub somewhere inside a predetermined area, in this case one measuring about 854,000 square miles. Searchers were to look for a submarine bobbing on the surface, probably without power or communication. Provided the sub’s structural integrity hadn’t been compromised, it would be safe there. Every sub in the fleet carried enough provisions on board to keep a crew alive for three months.

The US Navy maintained a constant presence off the Kamchatka Coast, and the USS Barb was sitting quietly in radio silence near Vladivostok when the Soviet Navy’s mobilization began. The Barb’s captain, Bernard “Bud” Kauderer, was initially confused by the frantic reaction. It was unlike anything he’d ever seen—an entire sub group racing out of port, with active sonar going full bore, and no apparent worry about detection. Kauderer ordered the Barb to follow the group from a safe distance, observing as these Soviet subs dove, resurfaced, then dove again, talking openly over the radio channels to fleet command and calling out, again and again, for a boat that never called back. “Red Star, come in. Red Star, come in. Red Star.”

Kauderer reported back to US Fleet Command and asked for orders.

“Stay on station,” he was told.

The search intensified. Two destroyers, three frigates, three minesweepers, two mother ships, and ten support vessels—in addition to the four submarines—participated in a methodical search led by planes that circled overhead. In total, thirty-six flagged vessels participated in the hunt for K-129, working day and night, using echo and sonar sounders and dragging photographic equipment that scanned the depths far below the surface. All the while, surveillance planes flew ahead—at least fifty-three took part—tracking the sub’s intended path, looking for any wreckage on the surface that could help narrow the search area. Over the next seventy-three days, Soviet planes would make a total of 286 flights over the zone.

Weather made matters worse. Winters can be brutal in the North Pacific, and the Soviet fleet ran smack into violent storms, with heavy snow, gale-force winds, and waves cresting as high as forty-five feet. During the early days of the search, the ocean was as wicked as it could be, with conditions registering at or near a 9 on the Douglas Sea Scale—a scale designed to express the sea’s roughness for navigation that only goes as high as 9. At that level, waves can reach fifty feet and the sea is described, bleakly, as “phenomenal.”

Dygalo joined the search personally, aboard a nuclear sub, and at snorkel depth, his watch officer wore a full diving suit over a fur coat and pants and was strapped using a harness and chain to an iron brace on the bridge. There, Dygalo recalled, “he bobbed up and down like a cork in waters foaming about his chin whenever the sub plowed into an oncoming wave.” On the downside of waves, the sub would nearly roll onto its side. “To make anything out in those seething waters, in those conditions, was highly improbable,” Dygalo later said.

All the while, American Orion-class antisubmarine planes circled overhead, constantly audible to the Soviet watchmen but visible through sky scopes only on the rare occasion when the weather broke and the clouds parted.

The biggest problem was that the Soviets didn’t actually know where to look; they knew only where the K-129 had been last—on March 7—and where it was headed—to the Hawaii station—so they focused the search along that line, looking for oil slicks, debris, or anything else on the surface that could indicate a disaster. The initial search zone was vast, more than eight hundred thousand square miles, and got bigger as the search failed to locate any signs of the sub, growing to 1 million square miles, an almost impossibly large area, especially considering another factor: the ocean’s depth. In that area of the Pacific, the bottom was nearly four miles below, and because all signs pointed to a catastrophic loss, the K-129 wasn’t likely to be found on the surface. In all likelihood, it lay shattered on the bottom, more than three miles below.​

The K-129’s return to port had been scheduled for May 5, and when that date came and went, the wives and parents back in Petropavlovsk, who’d been told almost nothing by the fleet leadership, began to accept that their husbands and sons weren’t coming home. They gathered in a square next to a monument erected for another lost sub, wearing black. Irina Zhuravina, wife of the submarine’s second-in-command, had been clinging to faint hope. “He loved life so much that he simply couldn’t die,” she told herself, and the friends from the fleet who fished with her husband and made caviar in their home kept coming by. “Sasha can’t die,” they told her. “He’ll come up. He’ll figure out a way.” For weeks, her eight-year-old son, Misha, kept asking the same question: “Where is Daddy? He’s never gone this long.” “Daddy’s at sea,” she told him.

Officially, the families were told very little. It wasn’t until September 12, six months after the K-129’s disappearance, that the supreme commander of the Soviet Navy issued an order stating that the sub had been lost while on duty in the Pacific and that all the men on board were “presumed dead.” That description wasn’t just insulting; it was financially cruel, because instead of the full salary and pension awarded to military men lost in the line of duty, it meant the families were awarded only a single lump-sum payment of fifteen hundred rubles plus a partial pension—the same pitiful amount they’d have been given if the men had died accidentally by slipping and falling.

Many within the fleet, including Admiral Dygalo, were ashamed of the Soviet response. Dygalo suffered a heart attack while writing personal letters to each of the families and was hospitalized for a month. “By the order of the Minister of Defense, K-129 was removed from the register of naval vessels, as though it never existed,” he later wrote. “Moscow decided that it was the end of the story.”