Since the Hugo nominations released recently have significant overlap with the Nebulas, it seems a relatively easy task to read the additional novellas, so I've started with this offer by Seanan McGuire.
Stephen and Chester Wolcott have carefully ordered lives, and have decided that they should complete their family with children. Though they're hoping for a matching pair of boy and girl, fate throws a spanner in the works when twin girls appear, Jacqueline and Jillian. With this inauspicious start, the utter lack of parenting abilities of the two new parents becomes rather obvious, and the children get a rather fraught upbringing.
Though they are helped through childhood by their father's mother, who acts as parental stand-in most of the time, they end up with a few personality quirks, which come to the fore when they find a hidden staircase in their dressing-up box. This starts them on their journey to The Moors, a mysterious land illuminated by a blood-red moon and occupied by werewolves, deep ones, scared villagers and people with an unhealthy fixation with necks.
Jack and Jill find themselves apprenticed to different masters, and must try and survive until they can find the way back to their world.
It's mostly a story of choosing a home, and whether that choice is voluntary or forced upon you.
Honestly, it's pretty brilliant. The children's earliest years have some strong character moments, with the struggle for self-determination in opposition to the world's expectations. It's a section that would normally be a simple setting up for the main "adventure", but there's a lot to unpack in it.
And when they begin to explore the hidden world, it's delightfully complex, even though it holds relatively closely to the traditional tropes. We have a Frankenstein of sorts, a cowed village and a gothic romance, but they're all given a humanising twist that makes it a joy of recognition rather than a re-tread of old stories.
Also had a fun sneaky Bela Lugosi reference. My only complaint would be that the ending feels a little abrupt.
Though I read this as a standalone, it is actually a prequel of sorts to Every Heart a Doorway. Will now definitely have to hunt that down.