Missile subs are relatively slow and vulnerable to attack. So to defend herself, K-129 carried two nuclear-tipped torpedoes loaded into the forward launch tubes, each one capable of sinking a US aircraft carrier, as well as a second set of conventional self-guided torpedoes in the stern bays to defend against attack from other submarines.

Boats like the K-129 were particularly critical to the Soviet Navy’s mission. The Pacific Fleet was still young, and these diesel-powered ballistic missile subs of the Twenty-ninth Division provided the most direct threat to America’s major West Coast cities—a threat that the Americans couldn’t easily track. The sub’s role was to patrol the Pacific quietly and stand ready to act in the event of nuclear war.

The end result of the schedule change was that Kobzar and his men were yanked out of shore leave they had earned, tearing them away from neglected hobbies, upcoming anniversaries, and family birthdays they missed all too often in the course of serving the motherland. Zhuravin, his wife, and their two children had joined several other officers and their families at a spa resort, where the pristine air of the Kamchatka peninsula helped clear up the respiratory irritation he had developed on the previous mission. But the arrival of a telegram announcing orders to return to port could not be ignored, and though the young captain had reservations about returning to sea so soon, with the sub in need of repairs, he knew better than to express that sentiment aloud.

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.