In the sunken city of Alante, Io is a descendant of the Fates who uses her ability to see and manipulate life threads to work as a private investigator. While investigating a series of impossible murders, she uncovers a conspiracy that threatens the city's fragile social order. To solve the mystery, she must team up with Edei Rhomes, a boy to whom she is unexpectedly bound by a rare and permanent thread of fate.