Synopsis for
Under Siege (1992) More at IMDbPro »

A band of ruthless mercenaries, led by psychopathic ex-CIA agent William Strannix (Tommy Lee Jones), board the American battleship USS Missouri BB-63 during her final voyage to steal its arsenal of nuclear Tomahawk Cruise Missiles. They arrive in the disguise of a group of musicians and caterers hired for a surprise birthday party for the captain, and they seize control of the ship with the help of the corrupt and psychotically unstable Executive Officer, Commander Krill (Gary Busey). They plan to sell the nuclear weapons on the black market by unloading them onto a renegade submarine Strannix had covertly stolen from North Korea while on a previous CIA mission. Several of the officers are killed during the takeover, including Captain Adams (Patrick O'Neal); the rest of the ship's company are imprisoned below decks in the forecastle save for stragglers in secured areas. Strannix and his men also take over the ship's weapon systems for defense, shooting down an F/A-18 Hornet, and plan on covering their escape by launching a missile strike into Honolulu that will obliterate tracking systems in Pearl Harbor (at the cost of many lives).

The only thing in their way is the ship's cook Casey Ryback (Steven Seagal), who is really a Chief Petty Officer and former Navy SEAL with extensive special-weapons and counter-terrorism training. He was relegated to his current posting for striking an officer who had gotten his men killed in a botched commando mission during the invasion of Panama. He had lost his security clearance and was only able to serve as a yeoman or a cook. Luckily, Ryback is a good cook and at the beginning of the film, he was making bouillabaisse for the captain's birthday.

Prior to the invasion, an anxious Krill provokes a brawl in the galley with Ryback. Ryback assaults the officer, and Krill, unable to imprison him in the brig without clearance (or attracting attention), detains Ryback in a freezer. After the ship is captured, Krill finally recalls Ryback and Strannix offhandedly sends two mercenaries to eliminate him. Instead, Ryback dispatches the unsuspecting mercenaries and proceeds to cause havoc amongst the boarders with the limited help of Playboy Playmate "Miss July '89" Jordan Tate (Erika Eleniak), an innocent civilian and stripper hired for the festivities. Krill responds by attempting to drown his own crew in the forecastle using the fire extinguisher system, and ambushing Ryback should he attempt a rescue. Ryback locates a group of sailors in hiding and with them engages a successful counter-strike, saving the crew and decimating a considerable size of Strannix's forces. As Strannix's men regroup, Ryback shuts down the Missouri's weapon systems, leaving the craft vulnerable to an incoming Navy SEAL team.

As the battle for the ship continues, the submarine crew shoot down both the Navy SEAL troop transport and its AH-64 Apache escort with shoulder-fired surface-to-air missiles. The Pentagon responds by ordering an airstrike that will destroy the Missouri and all aboard. Strannix regains control of the ship's weapon systems, and the Tomahawks are finally loaded onto the North Korean submarine, departing with Krill on board. With the aid of Jordan and his fellow sailors, Ryback uses the battleship's guns, still not yet decommissioned, to sink the submarine with Krill still inside.

Strannix, standing on the deck, suffers a major concussion from being in the proximity of the Missouri's guns as they are fired. Severely disturbed, he orders the remaining mercenaries out of the control room as he launches two nuclear-tipped Tomahawks towards Honolulu. One of the two missiles is destroyed by fire from a fighter jet, but the other continues on its course. As the sailors recapture the ship, Ryback finds his way into the control room, where he is caught off guard and captured by Strannix. Strannix becomes crazed and rants to Ryback about their mutual "master", letting his guard down long enough for Ryback to brutally kill him and take the launch codes needed to destroy the remaining missile. The holocaust on Honolulu is narrowly averted, as is the Pentagon's airstrike on the Missouri.

At the end, the remaining crewmembers are freed from their below-deck prison as the ship sails towards harbor. As he is checked by a doctor, Ryback kisses Jordan Tate as the crew looks on and cheers. The film ends with a ceremony for Captain Adams being held on the decks of the Missouri, showing the captain's casket with flag draped, and Ryback is shown saluting in his dress uniform in the final scene.