In 1959, the Soviet Union launches its first ballistic missile nuclear submarine, the K-19 — nicknamed "The Widowmaker" due to the many deaths that occurred during its construction. The ship is led by Captain Alexei Vostrikov (Harrison Ford), aided by executive officer Mikhail Polenin (Liam Neeson). Polenin and the crew have served a number of years and missions together but Vostrikov's appointment is shown to be aided by his wife's political connections; her uncle is a member of the Politburo. During an early inspection, Vostrikov discovers the officer in charge of the sub's nuclear reactors to be drunk and asleep on-duty. Against Polenin's advice that the man is "the best reactor officer in the fleet", Vostrikov sacks the officer and orders Polenin to request a replacement. The new reactor officer arrives direct from the naval academy and has never been at sea. During the K-19's official launch, the bottle of champagne doesn't break when it strikes the bow; the sailors glance nervously at each other due to this renowned sign of bad luck.
K-19 puts to sea for her trials. Vostrikov orders a series of diving maneuvers and during these, asks Polenin to simulate a number of emergencies including fires and flooding while he times the crew's response. He is not happy with their performance. There are a number of minor accidents during these exercises which result in injuries to crew-members. In addition, Vostrikov points out to Polenin that the crew are too slow and slipshod in their reaction and completion of these exercises. The crew begin to grumble about Vostrikov's demanding orders and authoritarian manner, but Polenin silences them when he visits the crew's quarters: "I heard there'd been some complaining. I thought, 'Not from my crew. Not on my boat'." Meanwhile, Vostrikov blames the officers for the crew's under-performance, accusing them of being soft on the men and lacking leadership.
The crew's performance improves and Vostrikov decides to carry out the K-19's first mission, which is to surface in the Arctic and fire an unarmed ("test") ballistic missile. Vostrikov orders the K-19 to submerge to maximum operational depth (300 metres), then surface rapidly at full-speed to break through the Arctic pack-ice which he estimates to be no more than 1 metre thick. Polenin regards this maneuver as dangerous and, during the surfacing procedure, storms off the bridge. After scraping along the underside of the ice, the K-19 finally breaks through and surfaces with no apparent damage. The test missile is launched successfully and the crew are both relieved and exhilarated by Vostrikov's bold maneuver. The crew are allowed some time off during which they play soccer on the ice and a group photograph is taken. Talking privately with Polenin, the sub's political officer expresses some confidence in Vostrikov, but Polenin asserts that the captain was "lucky today, that's all."
K-19 then receives new orders, to sail down through the North Atlantic and patrol off the US east coast "between Washington and New York." As the K-19 sails southwards a pipe carrying coolant to one of the reactor cooling system springs a leak and then bursts completely. The control rods are inserted to stop the reactor but without coolant the reactor temperature continues to rise rapidly. Polenin and the radiation officer are shocked to discover that back-up coolant systems have not been installed. Vostrikov orders the K-19 to surface so that he may contact Fleet Command and inform them of the accident and await orders. But upon surfacing they discover the long-range transmitter on the conning tower is damaged and they are unable to contact headquarters — Vostrikov assumes, ruefully, his surfacing maneuver in the Arctic caused the antenna damage.
The officers and crew-members in charge of the reactor discuss options. The radiation officer informs them that if the reactor temperature exceeds 1000° Celsius it will result in a thermonuclear explosion and may trigger the detonation of the sub's nuclear warheads as well. They have about 3–4 hours before this happens. Some suggest sending out a distress call on the sub's short-range transmitter and abandoning and scuttling the ship. Vostrikov is against this idea. Pavel, the radiation officer's assistant, suggests they can pipe the K-19's drinking water into the reactor to cool it. But they need to set up a system of pipes to transfer the water. Vostrikov approves the plan and the crew work feverishly, cannibalizing the sub to construct the piping system. The final phase requires sailors to enter the radiation-filled reactor room to weld the pipes together. In order to restrict exposure to the deadly, leaking radiation, they require three teams of two, working for no more than ten minutes at a time. Vostrikov calls for volunteers. Pavel and another crewman, Anatoly Zubachev volunteer to be the first team, but Vostrikov has to order others into the reactor. He orders the radiation officer in as part of the last team, to inspect the success of the welds. Polenin and the radiation safety officer then discover the K-19 has no radiation suits, only chemical suits. "They might as well wear raincoats!", exclaims Polenin. Nevertheless, with no other option, he lies to the men and tells them the chemical suits will protect them.
The first team enter the reactor and begin welding. Emerging ten minutes later and removing the suits, they are both suffering from severe radiation poisoning and are carried to their quarters where the doctor attends to them. The second team enters. Meanwhile, on the bridge, the captain, officers and crew monitor the reactor temperature which is climbing steadily. In the reactor room, the second team emerges just as badly poisoned as the first and are carried away. It is time for the third team to go in, but the radiation officer is overcome with fear and cannot bring himself to enter the reactor, despite the urgings of Polenin. Chief engineer Gorelov volunteers to go in his place. They complete the welding and to everyone's relief the reactor temperature begins to fall — the plan seems to have worked. But the submarine is beginning to fill with radiation as the reactor door is now breached, to allow the coolant pipe access. Polenin wants to seek help from a nearby NATO base on Jan Mayen. Vostrikov refuses to surrender his boat or crew and orders the K-19 to sail towards the USSR, under radio silence, in the hope that they will meet up with another Soviet submarine; Polenin is doubtful this plan will succeed as it relies on luck.
Vostrikov is informed that a helicopter is approaching; he and some of the crew climb out onto the deck, thinking a Russian ship has come to save them, only to discover that it is a US Navy helicopter from a nearby US destroyer. The destroyer is asking if the K-19 requires assistance. Vostrikov orders a reply in the negative; the men on the deck notice a crewman in the helicopter photographing them, and they drop their trousers and bare their buttocks at him. The helicopter flies away. Vostrikov refuses to allow the Americans anywhere near K-19. The US destroyer follows them at a discreet distance.
The chief petty officer (CPO) meets with the K-19's political officer in private. The CPO reminds the political officer that he is empowered to remove Vostrikov as captain, if he judges Vostrikov to be jeopardizing the mission. After a few hours and no 'friendly' ship sighted the weld connecting the temporary coolant pipe to the reactor fails and the reactor temperature again begins to rise dangerously. The radiation officer dons a useless safety suit and enters the reactor alone to fix the broken weld. Vostrikov again orders the K-19 to submerge, rather than abandon ship, angering the men. As the K-19 dives some torpedo fuel, spilled when the torpedo was stripped for pipes, ignites and causes a fire in the aft torpedo room. Polenin appears to doubt the captain, but goes forward to supervise the men fighting the fire. When he is gone the CPO and political officer produce pistols, point them at Vostrikov and the political officer announces he is replacing Vostrikov with Polenin as captain of the sub, and to surface immediately. Vostrikov is handcuffed to a ladder. With the torpedo room fire extinguished, Polenin returns and is told what has happened. "Good," he says and asks for the CPO and political officer to hand over their weapons to him. They do so and Polenin immediately orders Vostrikov to be released and the CPO and political officer to be placed under arrest, which they are. Polenin admonishes them for the attempted mutiny and re-asserts that Vostrikov is the captain of the K-19.
Vostrikov then attempts to re-order the crew of the K-19 to submerge, but Polenin interrupts him to say "Don't order them; ask them." Vostrikov explains the situation. If the reactor and the ballistic missiles explode while the K-19 is surfaced, the resulting nuclear blast will destroy not only the K-19 but also the nearby US navy ship and, most likely, the NATO base as well. As the K-19 has not been able to inform anyone in the outside world of her predicament, all the USA, Russia or anyone else will know is that a huge nuclear explosion has destroyed a US warship and NATO base. It could trigger World War III. The crew appreciate their wider duty and prepare to dive deep and scuttle the sub. But the radiation officer has spent 18 minutes in the reactor successfully fixing the weld, and the temperature begins to drop again as Vostrikov himself and other crewmen drag the fatally poisoned officer from the reactor. Just as Vostrikov orders the men off the boat so that he can scuttle it, they are rescued by another Soviet submarine. Vostrikov wants to move his crew to the other submarine, away from the radiation, but permission is not granted. He moves the crew anyway. Polenin warns him that he will be sent to the gulag, just like his father, for disobeying orders. Vostrikov smiles and says, "Its a family tradition, isnt it?" Afterwards, in an inquiry of the events, Polenin speaks highly of him. The inquiry acquits Vostrikov of any wrongdoing in the end, but he is never given command of another sub again.
An epilogue shows an aged Captain Vostrikov in 1989, putting on his dress uniform in a small flat and catching a train to meet up with Polenin. It is exactly 28 years after the accident; the Berlin Wall is shown to be coming down. Vostrikov grumbles about the inconvenience but Polenin informs him this is the anniversary of the day they were rescued. The commanders enter a cemetery where a number of the surviving K-19 crewmen are gathered by a gravesite. We learn that this is the first time the K-19 survivors have met since the incident, they were ordered never to meet or discuss the incident after the inquiry. Vostrikov is visibly moved as he greets the men and informs them that he nominated the men now dead of radiation poisoning (28 in total) for the distinction of Hero of the Soviet Union, but was told they were not "worthy" of the title as they died not in battle, but as the result of an accident. The men drink a toast to their deceased comrades.
(from Wikipedia)
