Kierse is a street thief who breaks into the mysterious Holly Library to steal a valuable diamond, only to be caught by its enigmatic and dangerous owner, Graves. Instead of killing her, Graves offers Kierse a bargain to stay and train under his tutelage to uncover the truth about her burgeoning magical abilities. As she navigates the secrets of the library and the supernatural world, she finds herself drawn into a complex relationship with her captor.