It may or may not be a don’t-understand, but no doubt it is a puzzle.
Some more covid (in)consistency comics.
Here the “consistency” issue arises when the character watches old movies.
Dreams also needs to be consistent!
A GoComics commenter commented: ” Nancy (the strip) has had a bit of an uneasy relationship with the pandemic. I don’t think masks have been needed in the same way they were in, say, Arlo and Janis or Luann or Betty, but it makes it a little weird when they’re needed for the joke.”
It took me (Winter Wallaby) an exceptionally long time to parse the sequence of events in this strip.