On the outskirts of Joya d'Arena, small villages fight for survival against the onslaught of sorcerers and raiders. Mara's village has been safe--so far--but Mara decides to escape anyway. Escape from her harsh, abusive father. Escape with her first love. But when their plans fall on the same day that the animagi burn the village to the ground, Mara faces losses that could destroy her. She's a survivor, though. She is going to make it through the mountains, and she is going to protect the refugees following her. Because there's a rumored safe haven . . . and some say they have found the Chosen One. 

Told from Mara's point-of-view, "The Shattered Mountain" is an alternate perspective of the beginning of the acclaimed The Girl of Fire and Thorns.

I have to give Carson credit--these prequels definitely serve to help round out the world and give us a different look at Elisa (or the role she fills).  In "Shadow Cats", told from Alodia's POV, we saw Elisa as a younger girl, frightened, but understanding so much more than Alodia gave her credit for.  Now in "The Shattered Mountain", though Elisa has a very small role near the end, Carson shows us how from the very first moment Mara saw that Elisa was special and would understand her.

This also serves as a way to establish the reason for a lot of Mara's early antagonism as well as the bond she shared with many of the children shown throughout the first two books.  In a matter of less than a hundred pages we see Mara go from a dreamer who saw freedom only in how far she could run to a leader, keeping a dozen or so children grounded and brave against impossible odds.

I wouldn't say that Mara is hard or grim; she has moments of such, but who wouldn't under such odds?  She is trying to keep frightened, starving, injured and grieving children alive while avoiding the Invierno who are everywhere.  She makes a lot of decisions that are hard and doesn't have a lot of time for coddling.  Survival is on the line and discomfort now could save their lives.

I already liked Mara from the books, so this was just icing.  This served to illustrate why she is such a good fit with Elisa.  I do think this was a story you could only fully appreciate if you had read the books first.  The details we learned throughout those books are fully explored here and thus all the more appreciated.