On the muddy banks of the Calumet River, a body has been found posed next to a series of mysterious glyphs and bearing wounds from a ritualistic slaying. Chicago detective Addie Bisset knows only one man who can decipher the message left by the killer: her friend Dr. Evan Wilding. A brilliant forensic semiotician, Evan decodes the etchings as Viking Age runes. They suggest either human sacrifice or righteous punishment. But to what god? And for what...