After befriending a mysterious horse during a summer in the English countryside, 15-year-old Zoe finds the strength to deal with issues she faces.

In a world cleaved in two by a massive barrier of perpetual darkness, a young soldier uncovers a power that might finally unite her country. But as she struggles to hone her power, dangerous forces plot against her. Thugs, thieves, assassins and saints are at war now, and it will take more than magic to survive.

It starts on a brutal murder before rewinding back 15 days to find out why and how, and most importantly who was responsible.