The Last Hour Between Worlds is a smart fantasy adventure, first novel on the Echo Archives, written by Melissa Caruso, and published by Orbit Books. A locked room murder that soon evolves to an adventure among the different layers of reality, progressively getting into weirder layers, with a sapphic cat mouse game that makes this a memorable read experience.

Kembral Thorne is spending a few hours away from her newborn, trying to enjoy those few moments in a new year party; but when the guests start to drop dead, she doesn't have an alternative than to investigate and try to solve the problem, as even at maternity leave, she's a Hound. Not only her is involved, as her personal nemesis, Rita Nonesuch, gets into the prowl, and both quickly identify a mysterious clock that sends them down an Echo each time it reaches the midnight; in each layer, time resets and a new people is assassinated to perform a sinister bound ritual. As they fall through layers, they will need to put aside their differences, and unravel the secret behind the clock and the murders.

It's refreshing to have a character like Kembral as the main lead; a mother that is on maternity leave and that is forced to the action because it means protecting the world for her daughter. A mature person that still has some grievances with Rika, and that has her own set of traumas; but as we descend, she will open herself to her nemesis, slowly developing a bond with her. Rika also fits perfectly into the duo, more snarky, but also has a good heart; there's a big revelation about her past that makes it have even more sense, and totally loved that sense that impulsed her to help Kembral.
The rest of the cast might be less memorable, but some of the Echoes that try to meddle with the mortal affairs are quite interesting, especially as we start to understand how this is a bigger plot over the own murders.

Carusso smartly plays with her concept of the world, a reality that each time you descend a layer gets weirder and more dangerous; the concept of starting with a party scene and develop from it in each reality is brilliantly executed. While we miss some details at the start, they are slowly woven into the picture, keeping an excellent pacing and throwing into the plot a sapphic subplot that works marvels.

The Last Hour Between Worlds is just the start of this series, but already I can say that we have a delicious fantasy adventure, and that you will especially enjoy if you are looking for a MC outside of the standards, a mother that is thrown into an adventure while still needs to keep herself safe for her daughter. An absolutely brilliant book, and a promising start to the Echo Archives.