This is nine short stories that are the length of a novel when put together, and you can consider this is be book 8.5, since five of the stories take place after the events of STAKED in series chronology. You also get adventures of Atticus in the past: The story of his raid on the Library of Alexandria, his meeting with William Shakespeare, a visit to San Francisco during the gold rush, and more. Two stories are narrated by the archdruid Owen Kennedy and one each by Granuaile and Perun.
Credits et all
Image and info taken from: https://kevinhearne.com/books/besieged/