Book 1, introducing Ridmark as the disgraced knight wandering the road. (After an introduction in which we learn that Mordred's bastard son led people from the disasters falling his grandfather's fall through a gate to a high fantasy world.)
Ridmark's asked to investigate the disappearance of a baptized dwarf, a friar who wanted to evangelize the orcs. He deals with accusations of pig theft, discovering bands of orcs in battle, and a rescue -- and then the sky burns with blue fire.
Meanwhile, a woman wakes with no memory, and with her clothing falling apart because of age when she moves. She remembers her name is Calliandra, and she's captured by orcs.
There's other rescues, fitful returns of memory for Calliandra and clues why she lost it, an underground cavern, a secret scroll of evil magic, a baptized orc who feels the ties of blood, a siege, a truce in caves, and more.