Hard-drinking Detective Inspector Leah Bishop accepts a transfer from Edinburgh to a Glasgow branch of Interpol. Once there, she discovers that her fellow officers are otherworldly beings, and they police the supernatural world. They have called her in as the first human to ever work at Caledonia Interpol. Her job is to investigate a crime considered unimaginable to the Fae: the first serial killing of supernaturals. Urban fantasy pairing the grit and dark humour of everyday modern Glasgow with Scottish folklore, Caledonia follows Leah and her Victorian selkie partner, Dorian Grey, as they investigate supernatural crime in Scotland's city of culture.