Following the mysterious disappearance of an oil rig and a reconnaissance mini-submarine in the Gulf of Mexico, scientist Dr. Margaret Adams (Nicole Dickson) initiates the Armada Program, a bold effort to deploy giant robots designed for deep-sea rescue. The three robots—piloted by Red (David Chokachi), Tracy (Jackie Moore), and Jim (Treach)—descend nearly 800 fathoms to the sea bed, where they uncover the mangled remains of the rig and confront the sea monster behind the disaster. Red pursues the creature against orders from Admiral Hadley (Graham Greene), prompting a broad mobilization that brings every East Coast naval fleet to the site.
Red bursts onto a beach to warn bystanders of the danger, but the monster strikes from the shadows, launching a brutal attack that tests the city’s defenses. An F-18 Hornet piloted by Spitfire (Jared Cohn) flies in to aid in the fight, helping to bring the creature down. Yet Red is arrested for disobeying a direct order, and he spends time in solitary confinement before a brief release by Adm. Hadley and a later medal honoring his actions.
In the background, Sheldon Geise (Steven Marlow) reveals a top-secret sonar program that has identified monsters hundreds of millions of years old, whose life cycles include laying eggs in crude oil and saltwater mixtures. Two eggs are found; one hatches into the monster Red and Spitfire defeated, while the other egg hatches later, unleashing havoc as it destroys a naval fleet and menaces the city. As Tracy and Jim race to free Red from confinement, they are aided by Lt. Wexler (Demetrius Stear).
Geise informs Hadley that the President has authorized a nuclear strike on the monster, but Hadley refuses and orders an evacuation of the base. The monster retreats after a Northrop Grumman B-2 Spirit drops a payload, yet the threat persists as a second egg hatches off the Atlantic Coast. Dr. Adams outfits the trio with special “halo” headbands that neurally link them to their robots, enabling faster reflexes through direct body movement, though the pilots feel pain for every hit the machines take. After a rapid crash course, the three pilots head for New York City to face the monster once again.
As battles unfold, Geise pressures Hadley and orders the USS Virginia to launch a warhead. Red jams the missile’s frequency, sparing the city from a nuclear catastrophe. In retaliation, Geise confronts Dr. Adams, only to be subdued by Lt. Wexler, who shoots Hadley in the arm in the ensuing struggle. Amid the chaos, Tracy’s neural level goes critical and she nearly collapses, forcing Jim to shield her while Red seizes the warhead and the monster, carrying both into the atmosphere. He detonates the device, blasting the creature into deep space before crash-landing back on Earth.
In the final scene, the three heroes regroup with Adm. Hadley and celebrate their victory at a local bar, sharing a quiet moment of tequila shots and relief after a harrowing ordeal.