U-Man Must Be Stopped! Captain America, The Human Torch, and Toro race to commandeer a plane to catch up with Namor and Bucky, who made off with their Atlantean aircraft. Meanwhile, Namor explains to Bucky that U-Man was originally a research scientist Meranno, whom he exiled for making overtures to the Nazis. He realizes that Meranno used his mad science to gain powers similar to his own and is now fully allied with Hitler.
Out near Bermuda, where U-Man's attack is about to take place, Betty Dean is in a small boat with other journalists waiting to see Churchill pass through. U-Man and his Atlantean henchmen capture the boat to use as a staging platform, disposing of all its occupants except Betty, whom U-Man realizes is Namor's friend and thus a fitting prisoner. He hits Betty and throws her below decks, leaving her for unconscious, but she rolls with the punch and surreptitiously makes use of the boat's radio while U-Man prepares to launch himself at Churchill's Berwick flying boat as it starts to fly over. The Berwick starts to pull up and away thanks to Betty's message, but U-Man still manages to grab hold of it. Before he can do any damage, Namor catches up and attacks him.
With the Torches speeding up Cap's plane by grabbing onto each wing and acting as jet engines, the remaining Invaders soon join the fight as well just as Nazi U-Boats begin to surface to ensure the Prime Minister doesn't get away. The battle is ultimately disrupted when a mysterious whirpool-like portal opens in the sky, threatening to suck in enemy and ally alike. The U-Boats disappear into the portal while the flying Invaders work together to keep the Berwick from joining them. Churchill catches a glimpse of a dinosaur through the portal just before the phenomenon passes. With his backup gone, U-Man and his henchmen flee, leaving the Prime Minister and his pilot to fly on to Bermuda safely.
