Captain Marvel is the Marvel Cinematic Universe's second period piece film, the first having been Captain America: The First Avenger, all the way back in 2011. Set in the middle of World War II, the movie explained Captain America's time jump to the present by popping him on ice for 60 years. Captain Marvel is set in 1995, but no convenient explanation was given to explain her absence since. Where has Captain Marvel been for 25 years? Warning: Spoilers for Captain Marvel follow.
In Captain Marvel, Carol Danvers discovers everything she knew about herself since waking up on the Kree homeworld, Hala, six years ago was a lie. She's not half-Kree, she's human, given a Kree blood transfusion by Yon-Rogg. Her powers don't come from the Kree blood or the device on her neck. The gadget is suppressing her abilities, not enhancing them.
She gained her powers when she blew up the engine she and Dr. Lawson were testing, and her body absorbed the energy in the blast. Lawson's invention was running on power gained from the Tesseract, which is actually the Space Stone. In short, Carol Danvers is a human infinity stone.
So where has Carol been since discovering all this about herself? One of the other things she learns was why she blew it up. Lawson was really a Kree named Mar-Vell. She wasn't working for her people though. She was a rebel Kree, working to save the Skrull people. The Kree taught that the Skrulls were a race of terrible alien shapeshifters, trying to infiltrate other worlds. In truth, they were homeless, shapeshifting to hide. The Kree were hunting them down.
Danvers didn't do it to keep it from falling into Skrull hands. She blew the engine up to keep the Kree from having it. Danvers had spent six years as part of a systematic plan to commit genocide without knowing it. When she leaves Earth at the end of the movie, she's going to take the Skrull people somewhere safe, as a way to make up for the crimes she committed. After that, she plans to stop the Kree from doing it to others.
Fighting the Kree seems to be where she's been this whole time. Some have thought her time traveling; others assumed she was in the Quantum realm. No, she's just been busy elsewhere in the universe, saving other worlds from the Kree. She hasn't been back to Earth because, as far as she knew, they didn't need her.
She told Fury the pager was For Emergencies Only, and bless him, he took her seriously. Part of him most likely thought he didn't need her anyway. He found other heroes. He found Iron Man, Captain America, Thor, and Hulk. Seriously, consider the Avengers roster in Infinity War, which was 22 main leads strong. Fury figured they had it covered.
They didn't have it covered.
Fury paged her because finally, it was an emergency. As the mid-credits scene shows, she came.
Fans can't wait to see how this goes. Avengers: Endgame arrives in theaters on April 26, 2019.