In 1861, at the onset of the American Civil War, the Union forces stationed in Gosport, Virginia, prepare to leave. The Confederate forces are poised to take Gosport. Before departing Gosport, the Union forces destroy the port facilities, docks, warehouses and a few ships that cannot sail. One of these ships is U.S.S. Merrimack, a 40-gun steam frigate. However, the Union forces fail to destroy the dry dock. The Confederates use the dry dock to repair the Merrimack and cover it with iron plates in order to turn it into an Ironclad. The Confederates intend to use the ironclad ship, re-named C.S.S. Virginia, to attack the Union wooden warships blockading the Confederacy.
Washington D.C. gets wind of these Confederate plans and decides to send two spies, one man and a Southern belle, to Virginia to steal the exact specs of the new Confederate ironclad ship. This information is vital for the Union in order to allow it to build a more powerful ironclad ship than the Confederate one. While the Union spies work in Virginia to steal this information the Union shipyards start the construction of an ironclad ship, the U.S.S. Monitor.
In the meantime, the completed Confederate ironclad ship wreaks havoc among the Union warships blockading Virginia. After 3 months, the Union ironclad ship is ready and without further ado it makes its way to Virginia. Its first mission is to protect the few remaining Union warships still blockading Virginia. The Confederate ironclad has a tall profile but is armed with 10 cannons while the Union ironclad has a much lower profile but is armed with only 2 cannons mounted in a rotating turret. Both ships face a tough upcoming fight among the treacherous sand bars of the shallow waters of coastal Virginia.
In the morning of March 9th, 1962, the two opposing ironclads finally meet in battle.