The film follows Casey Ryback (Steven Seagal), a former Navy SEAL now working as a cook on the Missouri during its final voyage before decommissioning. What starts as a celebratory event for the captain’s birthday quickly turns into a nightmare. A rock band led by the sinister William Strannix (Tommy Lee Jones) is on board, but their true mission is far more dangerous. Strannix, a rogue ex-CIA operative, teams up with corrupt officer Commander Krill (Gary Busey) to hijack the ship and steal its nuclear weapons.

As the terrorists take control of the battleship and hold the crew hostage, Ryback’s hidden skills come to the forefront. Using his SEAL training, he transforms from a cook into the ship’s only hope. In a relentless one-man assault, Ryback fights back, taking down the terrorists one by one in intense hand-to-hand combat, gunfights, and daring maneuvers.

Under Siege is renowned for its gripping action sequences, including explosive set-pieces, fierce combat, and heart-pounding tension. Seagal’s portrayal of the calm and deadly Ryback became a defining moment in his career, solidifying him as a major action star of the 1990s. Tommy Lee Jones and Gary Busey also shine as the villains, adding complexity and depth to their roles and making for memorable antagonists.

The film was both a commercial and critical success, praised for its well-executed action scenes and fast-paced suspense. Often compared to Die Hard for its “hero versus terrorists in a confined space” setup, Under Siege remains a timeless classic in the action-thriller genre. Its success led to a sequel, Under Siege 2: Dark Territory (1995), which moves the action to a hijacked train.