The first third of this story is straight-up historical fiction, tracing the lives of two young men caught up in the French Revolution, with little speculative about it (it is, however, gorgeously, shamelessly queer!). About a third of the way in, though, René and Armand pause in a field and encounter the titular mare, who is not at all what she seems.
The threads of René, Armand, and the mare weave together throughout the French countryside, as the two men seek to find a way to Armand’s mother’s village, and thence to Germany and safety and security away from the blood of revolution. No path can be straight or easy where the Mare of Meuse travels, but when Armand and René’s hopes are dashed, she is there to find a new way into the future for them.
This was a lovely and emotional story.