Sweeney Cassidy is a freshman at the University of the Archangels and St. John the Divine, where she meets the mysterious Angelica and falls in love with the strange and beautiful Oliver. She gets tangled up in sinister, supernatural events involving a secret society and the awakening of an ancient, malevolent goddess.

According to the afterword for the short story "The Bacchae", found in the collection Last Summer At Mars Hill is another take on ancient Greek myth that prefigures this book. They both involve murderous cults of women. Author Elizabeth Hand has said that she wanted to show that ancient goddess cultures were not all as peaceful and idyllic as we tend to think