There isn't much to say here; we're setting up for the next one.
We begin in Arkham Asylum, and we bear witness to a literal rogue's gallery of Batman villains (we see Scarecrow, Joker, and other Justice League villains I am less familiar with). Despite my lack of knowledge of those comic universes (apart from what I've seen in the movies), the borrowing of elements gives the illusion that the world in which Dream operates is extremely complete, very well-defined. If we wanted to learn more, there are a whole trove of comics to dive into, but if we don't, we are satisfied that the world is out there.
And, thankfully, no knowledge of the Justice League is required; Gaiman is not being referential as a coverup to a thin plot. He knows exactly what he's doing, and defines all his characters clearly in THIS universe. That is powerful. How else would we come to be shocked at the callous murder of one of the "passengers" in the story, poor Rosemary? In less than ten pages, we know enough about her to genuinely mourn her death. John Dee's vicious act could not have been predicted, but didn't seem out of character.
But the most important plot point in the story is of course Dream's ruby. He does not know that Dee has somehow modified it to poison him. Again, we see him taken down by a slightly better than average human. So in the running stakes so far, no matter how powerful we know Morpheus to be, he's not there yet. His command has not yet returned to him. But for some reason, I get a sense that the moment is near. The ruby is the final talisman, after all.
Also I think I've identified the first Sandman 'trope' (we'll see if this stands true later in the series). If ever we're caught in the nightmare of a character, we know they're in for a rude awakening by the Dream Lord himself. In this issue's episode of "Methinks Morpheus is On His Way," we are in the mind of Scott Free, one of the new Justice League heroes, trapped in an Oedipal nightmare about his grandmother. And then he's dragged back to the office to search for the ruby.
We learn about the universality of Morpheus, even on Mars he exists and is exalted. But I'm finding it a little bit frustrating that he is so all-powerful, but his talismans are so mundane; they can be handled, bought, sold, traded, and even modified by mere humans. Something about that doesn't ring right to me. But we have yet to discover the true value of the items, except that they are central to Dream's power.
Next episode: John Dee Goes Batshit Crazy