Captain America (1968 1st Series) #423

"War Zones" Guest-starring the Sub-Mariner. Script by Roy Thomas. Pencils by M.C. Wyman. Inks by Charles Barnett III.

It's a tale from Captain America's earliest days as America is debating whether or not to get involved in the burgeoning world war taking place across the Atlantic Ocean. Cap and Bucky are at the White House receiving an award from President Roosevelt when suddenly the Sub-Mariner crashes through the window! The Avenging Son is enraged! Why? And what does he want? The answers will have to wait as Prince Namor abducts FDR and takes the president to an unknown island! However, the future star-spangled avenger discovers Mr. Roosevelt's location and becomes a one-man rescue mission! Can a young Captain America defeat the mighty Sub-Mariner? And what about that German U-boat operating in the vicinity?! All hail to the chief! 

32 pages. Cover price $1.25.