Major spoilers for Avengers: Infinity War.
Avengers: Infinity War's end-credits scene is an exciting cap to the movie, bringing back Nick Fury and setting up Captain Marvel. However, it also leaves some pretty big questions about where Carol Danvers has been all this time - and why Fury's only calling her now after a decade of major threat.
Avengers: Infinity War goes all in with an uncharacteristically grim and violent ending. While the MCU has had shades of darkness here and there, it's never gone so far off the deep and as Thanos murdering his adopted daughter and weeping over the sight of her bloodied and battered body on the rocks below, to say nothing of what happens when he finally his fingers. To hammer home the darkness, unlike most MCU movies, there's no end-credits animated montage or even a mid-credits stinger; just a solemnly dry cast roll and Alan Silvestri's melancholy score.
However, this is a final stinger after the end of the credits, and it's a doozy: Nick Fury and Maria Hill, absent since Phase 2, witness random people dying, fading into dust. In a panic after seeing Hill suffer the same fate, Nick sends out a signal on some kind of paging before being reduced to cosmic dust, righteously cursing his predicament as he finally dies. As his remains are blown away by the wind, the camera focuses on the device, which receives a message, in the form of a familiar logo: that of Captain Marvel, who will have her own movie in 2019, just two months before the untitled Avengers 4.
Of course, this raises one interesting question: where has Carol Danvers, AKA Captain Marvel, been all this time?
Captain Marvel Missing in Action?
The upcoming Captain Marvel film (currently slated for March 8, 2019) will be primarily set in the 1990s. Clark Gregg and Samuel L. Jackson will appear as Agent Coulson and Nick Fury, but the cast also includes Lee Pace and Djimon Hounsou, who are reprising their roles from the intergalactic adventure, Guardians of the Galaxy. Therefore, it's likely that Captain Marvel will serve as a bridge between Marvel's earthbound and cosmic corners, much like the first Thor back in 2011.
The device Fury uses to contact Carol Danvers looks like a sci-fi version of a classic 1990s beeper, complete with an old-timey, low-resolution display. Perhaps it has been in his possession since the 1990s, for use as a last resort in the direst of circumstances. If this is the case, then the sudden, instantaneous death of half the universe would certainly qualify as dire.
On the other hand, if Captain Marvel has always been in Fury's back pocket, then why is he only calling her now? After all, circumstances were dire when Loki opened up a portal above Manhattan, through which flowed legions of alien warriors. They were pretty dire when Malekith the Dark Elf tried to merge the realms and return all reality to darkness using the mighty Reality Stone. And she'd have made quick work of Ultron. Why didn't Fury call her then?
Nick Fury's Panic Button
Perhaps Fury had faith in The Avengers. Whether together or separate, he knew they could protect the Earth and take care of threats like Malekith, Loki, and Hydra. His faith, while not misplaced, was simply not enough – Thanos won. Half the universe is dead. Cold, logical, and unfeeling balance has been achieved.
Maybe Captain Marvel is training on another planet, or perhaps she's sworn off conflict and won't return to battle unless it proves absolutely necessary. Maybe she and Fury had a falling out, and his pride kept him from asking for her help earlier. Or perhaps she's somehow out of the time stream, explaining how she can jump 20 years into the future without (presumably) aging a day. Whatever the case may be, it's a sure bet that answers will be uncovered next March, when Captain Marvel his theaters.