Dark Earth is a well-researched and interesting story about two sisters in Dark Ages Britain. When Blue and Isla’s father dies, they are abruptly thrust into peril. Isla has been working in her father’s forge for some time, which is believed to be against the gods’ will. Only Isla knows the secret of forging the mythical swords known as firetongues. This is a valuable skill that the men from the settlement would kill her for. To hide their father’s death and escape from their island, the sisters must work together to find sanctuary.