Steve returns to Wakanda. He's sad to hear that T'Chaka has died. He offers his shield back to T'Challa who says no.
During the dark days of the early 1940s, a covert U.S. Military experiment turned Steve Rogers into America's first Super-Soldier, Captain America. Throughout the war, Cap and his partner, Bucky fought alongside infantry and with a group of heroes known as the Invaders. In the closing months of World War II, Captain America and Bucky were both presumed dead in an explosion. Decades later, Captain America was found trapped in ice and revived in the modern world.
This is the segment at the end of First Avenger but prolonged as we see him take on Black Widow, Hawkeye, Mockingbird, The Cavalry, etc.
Cap fights the vampire Baron Blood alongside Union Jack, killing him
Cap goes after Warrior Woman on the lookout for something game changing. Steve meets T'Chaka and the two fight before realizing they're on the same side. T'Chaka says the vibranium for the shield is stolen, Cap offers it back. T'Chaka says he may borrow it for the war.
Split this into two stories: one is Warrior Woman intro. The second is Warrior Woman and Master Man go to Wakanda.
Bucky is lost and assumed dead
Red Skull opens a portal to another dimension (room for other Commando adventures)
Steve goes behind enemy lines to rescue soldiers
Steve Rogers is selected, he goes through basic training, he gets injected, Erskine is murdered, Steve fails to capture the Hydra agent
We're good! Get your helmet on, Scott. I'm gonna send you back a week, let you walk around for an hour, then bring you back in 10 seconds. Makes sense? Why would I be? Why would, why would I be scared of that guy? I'm the one who killed that guy, remember? Anyone else here killed that guy? Nope. Didn't think so. Korg, why don't you, tell everybody who chopped Thanos' big head off. These are Pym Particles, alright? And ever since Hank Pym got snapped out of existence, this is it. This is what we have. We're not making any more. Okay, so, uhh...
We need you. You're new blood. Bunch of tired old mules! Yeah, we boarded that highly suspect warship Danvers pinged. What I'm saying is, time works differently in the Quantum Realm. The only problem is right now, we don't have a way to navigate it. But what if we did? I can't stop thinking about it. What if, we could somehow control the chaos, and we could navigate it? What if there was a way to enter the Quantum Realm at a certain point in time but then exit at another point in time? Like... Like before Thanos. No, you accidentally survived. It's a billion to one cosmic fluke.