My memory of  McHugh’s successful first novel, China Mountain Zhang, is now 20 years in the past, but what I do remember of it includes her resolve to tell a human story amidst an original and interesting mélange of future extrapolation involving foreign countries, future entertainment, and a certain amount of “alienness” right here on Earth.   This was well executed and well received enough to earn her a Hugo nomination, pretty good for a first novel.  Her followup a couple of years later then was Half the Day is Night, a longer and maybe somewhat more focused novel that still maintains many of the same characteristics.  Here she presents an indeterminately dated future where large cities exist at the bottom of the ocean, there’s a large amount of backstory that is left unexplored regarding how these cities came to be and even gained their independence, never mind the economics and politics of how they actually function.  Instead, McHugh focuses on just a couple of characters; Mayla, a senior loan officer at a Hawaiian bank who has lived in the underwater city of Caribe her whole life, and David, her new French/Asian bodyguard who comes there for the first time to start his new job.  There’s a decent sized supporting cast, one thing that McHugh does better than nearly everyone in SF is her attention to detail in making her characters distinct, real and believable all the time, pointing out their chronic aches and pains, their self-doubt even as they assert themselves, their ambivalence and confusion in times of crisis.  Each chapter switches viewpoint between the two protagonists, allowing the reader to get inside their heads in roughly equal measure.

The plot goes puts them through some political/financial intrigue that ends up with both of them independently on the run, and much of the second half of the book is devoted in their planning an escape from the quasi-totalitarian government, which involves acquiring bogus travel documents, since you’re miles underwater and can’t just grab a car and head out of town.  While the mechanics of this quest are well paced and compelling, an awful lot is left unsaid in the interest of keeping the focus on the getaway.   Why do Caribe and its neighboring city-state of Marincite really exist? How can they be so huge, with multiple levels each with their own artificial lighting?  McHugh puts us in this world presumably for a reason, but basically the same story could have been told if they were all living on an island.  And in terms of the main characters’ need to be on the run and attempt escape, it’s a bit vague why they feel the need to run, since they didn’t really do anything wrong and it doesn’t seem as if the authorities are really pursuing them actively anyway.

Reading this book nearly 20 years after it was published, it also feels a bit retro, which isn’t McHugh’s fault, but you can’t help but notice the lack of instant communication and ubiquitous access to information that we take for granted.  People still make anonymous calls from a public vidphone booth, and documents are still mostly paper.   This is an inherent danger in writing this kind of story, but it’s still very much worth reading and leads to a satisfying conclusion.  It’s obvious that a lot of care and craft went into putting this story together, while more backstory or more dependency of the plot on the setting would have been useful, it would have also likely expanded the overall size of the book.  McHugh focuses on the story she wants to tell, and produces a memorable, involving story.