Gaiman returns to the character and story that made him famous (and wins the graphic story Hugo award by doing so).
This is a prequel to the original story. In that, you’ll recall (or if you don’t you should go and read them), Morpheus, the Lord of Dreams, starts by being captured by a wizard as he returns exhausted from an earlier adventure.
This is that earlier adventure. And it’s right up there with the rest of the Sandman stories. Highly recommended.