She Fell Away by Lenore Nash

Britt's take

An intricate thriller set in New Zealand with time jumps and dual narration that keeps you piecing together clues—I only caught on right before each reveal. Lake is a flawed, interesting protagonist with her own motives and questionable backstory. Starts slow but picks up around the halfway mark. Dark but not pitch black—a good pick when you want a thriller that's unsettling but not too unnerving.