Full story of avengers 4
Answers
When one of Thanos's "children" was trying to take the Time Stone from Doctor Strange, Doctor Strange told him that there was a "simple, but powerful" curse on it. Doctor Strange must've taken the curse off to put the fake necklace on so Thanos couldn't forcefully rip it off later in their fight. I think that when he took the curse off the Stone, he had time to look back in time and tell Captain Marvel, and Nick Fury to get two of those transponders from the after-scene from Avengers Infinity War. He told Nick Fury to press the button when The Snap happened. And he told Captain Marvel to go into a part of the Quantum Realm where time was very slow so she would only have to wait a few hours or something, for years to pass. And when Captain Marvel's transponder went off she would leave the Quantum Realm, and save Ant-Man on her way out. Then she would blast off into space to save Tony Stark and Nebula, and go back to Earth. During all this, Captain America is making a plan. His plan is similar to Loki's plan when Loki attacked New York. Erik Salvig and Bruce Banner will work together to open a portal to the Space Stone. (Loki did just that. He was able to portal right into that Shield base, where the tesseract was, in the 1st Avengers movie.) Erik Salvig has had experiences with these types of things, like in a few of the Thor movies and when Loki brain-washed him so he could work with the tesseract. So if they find the space stone then they find Thanos. But they may need a powerful power source. Like how they were able to destroy the mind stone with Scarlet Witches’ powers. But Scarlet Witch is dead. So maybe when Captain Marvel gets back, she can use her powers to do something to help them. Then they can open up a portal to the Space Stone, which is where Thanos is. Then the can beat him up and take the Stones and fix everything.