(Star Spangled Comics I #2) - Captain X was on Atlantic patrol duty when he spotted a u-boat attempting to sink a U.S. supply ship, and intervened. In his civilian identity he reported Captain X's latest exploits, and was asked to mentor new journalist Simons. He met with a high-ranking R.A.F. commander to propose building floating seadomes to fill the need for more Atlantic ports, and to do it in secret off the coasts of Ireland. Simons was actually a Nazi spy, started to suspect that Dare was Captain X, so he reported his proposal and sent Nazis to kidnap Dare. Dare foiled them, and realized Simons was a spy. He told the R.A.F. to find a more secretive location, and kept the Irish base as a front. When the Nazis attacked Captain X shot them down, and exposed Simons as a traitor.

(Star Spangled Comics I #3) - Captain X was on patrol when he saw a Spitfire disappear from the air and the pilot tumble out into space. He saved the pilot, and surmised that the Nazis had some sort of metal dissolving gun. He borrowed a spitfire to make himself a target, and had Stuffy follow him in Jenny. After the Nazis dissolved his Spitfire he found their lair, and Kurt Graff, the inventor of the gun. The Nazis captured X, and Gaff couldn't resisted giving X another demonstration of his weapon before ordering the soldiers to shoot him. They didn't count on the demonstration vanishing their bullets, so X easily overpowered them before loading the weapon aboard Jenny to aid in the R.A.F.'s war effort.

(Star Spangled Comics I #4) - Dare’s editor gave him the unreasonable assignment of learning if the Germans were going to attack from Norway, so he met with one of his R.A.F. friends and learned that he’d been reassigned to naval duty. This seemed like circumstantial evidence that Nazi did plan an attack, so he flew to Norway, and allowed Stuffy to accompany him since he asked so nicely. He saw the Germans preparing for their invasion, and prepared to leave and warn the British, but Stuffy’s bumbling led to his capture. He was guarded by a soldier who fancied himself an opera singer, so X played on his ego so they could perform a duet in his cell. He took the guard’s firearm, escaped, and was picked up by stuffy. He warned the R.A.F. about the pending invasion of Scotland, and X and the R.A.F. flew off to bomb the German barges. X noticed that the guard he’d tricked was the only man aboard any of the barges, so he halted the bombing, swooped down in jenny, and took him aboard. The soldier revealed that the barges were packed with nitroglycerin to blow the R.A.F. out of the sky if they attempted a bombing, and he’d been placed aboard as punishment for letting x escape. X commanded the R.A.F. to fly out of range of the explosives before releasing their payloads, saving the day. X was grateful for the soldier’s help, so he handed him over to Stuffy, and told him to make friends.

(Star Spangled Comics I #5) - Captain X received a radio distress call from Egypt when Nazis using semi-aquatic water tanks to destroy Egyptian forts and make their way to the Suez Canal. He realized the RAF didn't have any planes to spare, so he rushed to Egypt in Jenny, and after leapig from his plane, he went to work on the futuristic tanks with an acetylene torch. He commandeered one tank, and used its torpedoes to destroy most of the fleet. One tank remained, and tried to destroy the Suez canal, but he boarded it and set it off course so the torpedo misfired. Captain X handed the Nazis over to the navy and flew off.

(Star Spangled Comics I #6) - While walking through Piccadilly Buck was caught in an air raid. Debris from a bombed building struck a woman on the head, and Buck took her to safety. She revealed that the blow made her recover her memory. She was in another air raid in Germany some years ago, and came out of it an amnesiac. German soldiers convinced her she was a spy, and she’d recently sent convoy plans for an American supply company to Germany. She wanted to undo her mistake, so Buck changed into Captain X and headed for Kiel, the Nazi’s biggest naval bvase. He commandeered a mounted cannon and started blasting moored u-boats. The Germans were forced to hurry up their mission, and sent their remaining u-boats to America. X followed them in Jenny, and every time he saw a periscope he swooped in and smashed it with an ax. The blinded u-boats were forced to surface and were captured by the U.S. navy.

After many successful missions Captain X was transferred to operating behind enemy lines. He was first given a shore-leave in Atlantic City, where he met a young woman named Patricia. They had an affair, and he returned to Europe, unaware that she was pregnant. Captain X served until 1945, after which he searched for Patricia, but found she was happily married, with a two-year old son he didn't know was his.