Set in what author Kristin Cashore describes as an alternate world, Fire gives more insight into characters and locations found in Graceling.
Summary from Goodreads:
Beautiful creatures called monsters live in the Dells. Monsters have the shape of normal animals: mountain lions, dragonflies, horses, fish. But the hair or scales or feathers of monsters are gorgeously colored-- fuchsia, turquoise, sparkly bronze, iridescent green-- and their minds have the power to control the minds of humans.
Seventeen-year-old Fire is the last remaining human-shaped monster in the Dells. Gorgeously monstrous in body and mind but with a human appreciation of right and wrong, she is hated and mistrusted by just about everyone, and this book is her story.
Much like Katsa (from Graceling) has special abilities, so does Fire. Fire is beautful, beautiful enough to inspire madness, anger and other horrible feelings, but her true gift is that she can enter someone's mind and talk to them. She uses this gift at the behest of the royal family to interrogate spies, but later, on the battlefield to soothe the wounded.
I hesitate to call Fire a prequel to Graceling, even though it takes place before Graceling and gives more background information to Leck. I prefer to think of it as a parallel novel as Leck is the only crossover character, its set in a neighboring kingdom, and is really a stand-alone novel; you don't need to have read Graceling to read and understand Fire.
I really enjoyed Fire. The story was fast-paced and interesting, and the characters were well thought out. I gave it a 4 out of 5 on Goodreads. At the end of the book, Cashore talks about a third novel, Bitterblue (a key character in Graceling, and Leck's daughter). I can't wait to find it!