Kenneth Reynolds and Raymond Jordan are best friends and happen to be U.S. Navy officers. Kenneth is also engaged to Raymond's sister. However, the outbreak of the Civil War causes a riff in their relationship when Raymond stands with his native Virginia home and Kenneth remains on duty as a Northern officer. When a order to burn his own ship is ordered from the top, Kenneth instead sinks it and is dishonorably discharged. Meanwhile, John Ericsson, Kenneth's uncle, has designed a new battleship named Monitor. Kenneth is restored to duty as a crew member on the new ship. Eventually the war pits Kenneth, on board the Monitor, against his friend Raymond, serving aboard the South's own ironclad, the Merrimac. A naval battle ensues, one that will go down in history.