So, the stage was set last issue: Captain Mar-Vell is imprisoned in the negative zone, but he and Rick Jones can switch places. Whichever one is in the zone can still talk to the other one. So it’s a hybrid between Shazam, a character stuck in litigation, and Firestorm, a character who wouldn’t be invented for another 20 years.
These two issues are both done-in-ones that essentially root this conceit. Rick is walking around, a problem happens, he transforms, then he switches back at the end.
I think, though, that this is the first time Rick Jones played guitar in front of an audience. They don’t like him, and he punches a critic in the face. Hm.