Lieutenant Kenneth Reynolds and his good friend, fellow naval officer Raymond Jordan, go ice-skating with their girls in anticipation of being called to war. Reynolds' beau, Constance (Connie) Jordan, who is Raymond's sister, accepts Kenneth's marriage proposal. Meanwhile, at a government war council discussing the secession of six Southern states to form the
Confederacy, two officials from
Virginia are asked to declare their loyalty to the Union. Captain Buchanan resigns from the Navy to join the Confederates, while Commodore Jordan remains. A similar loyalty test confronts Raymond, who does not want to be separated from his fiancée, Captain Buchanan's daughter Julie, and leaves to join the Confederates in Virginia. Kenneth decides to stay with the Union and is put in charge of . When the ship is attacked by Confederate troops at
Gosport Navy Yard, Kenneth receives orders to burn the ship, but defies the orders and sinks the vessel to save the hull and engines. He is
court-martialed and
dishonorably discharged from the Union Navy. He cannot find another job because everyone considers him a traitor, so he goes to help his uncle
John Ericsson complete his new design of
USS Monitor, an
ironclad warship. The Union learns that the Confederates have
salvaged Merrimack and refitted her in iron as the
CSS Virginia. Kenneth encourages his uncle to submit to the government his design of the ironclad
Monitor, which features a unique revolving
gun turret. Though the Navy has accepted the plans of Bushnell, another shipbuilder, Commodore
David G. Farragut smooths things over and helps everyone see that the
Monitor is a better choice to engage in battle with the enemy. Not enough volunteers answer the call to man
Monitor, so Kenneth is accepted despite his dishonorable discharge. Meanwhile, Raymond has been named third in command on the CSS
Virginia. When Connie finds out that Kenneth will be fighting against her brother, she is unable to forgive him. Though Kenneth still wants to be with her, he must fulfill the call of duty. The
Battle of Hampton Roads finds
Virginia attacking and sinking and in the harbor. The next day,
Virginia approaches and
Monitor engages it in battle. Lieutenant Worden is wounded and Kenneth is put in charge of the second gun. After further exchange of gunfire, Raymond suggests that
Virginia pull up alongside
Monitor and
board it. Through the
gun hole, Kenneth sees Raymond approaching at the head of the boarding party and is distraught that he must kill him, but orders his men to fire both guns. The boarding party is repulsed and
Virginia backs off. After he returns to civilian life with an honorable discharge, Kenneth tries to renew his relationship with Connie, who is grief-stricken over her brother's death. The two meet President
Abraham Lincoln on their walk by the
Potomac River, and the president encourages them to pursue a future of peace. Connie is comforted and resolves to renew her relationship with Kenneth. ==Cast==