The trailer explains pretty much the whole premise right there. Each of them has powers (who cares where they came from?), and they’re all entangled so they swap places when they use them.
If you want deeper backstory, the upside is that the two shows that contain it are among the best shows Marvel has done so far.
quicken@aussie.zone 11 months ago
No serious answer: All of it. Including both Hulks.
Serious answer: Ms Marvel is probably all you need. The characters are not too deep and if you hate Ms Marvel you probably wont like this.