This book is a continuation of the story that began in 'Knife' and continued in 'Rebel'. I like the fact that each book is told from a different viewpoint but that we still get to hear lots about the protagonists from the previous book. 'Arrow' begins soon after the rebel uprising in 'Rebel'. The main character is Rhosmari, one of the Children of Rhys, having lived all her life on the sheltered human free islands she gets quite a culture shock when she sets out alone to try and bring the Stone of Naming back to her people to avoid any confrontations between her people and the rebels they didn't wish to help. Sadly Rhosmari's plan doesn't work out exactly as she had hoped and she is thrust right into the path of the evil Empress herself.
Almost all of the characters from the previous books are present i this one, with most of the Oakenfolk and their humans, Paul, Peri and Timothy making a re-appearance. We also learn more about some of the Empress's followers, particularly Martin (the faery who stabbed Timothy in 'Rebel'. This book is interesting as we follow Rhosmari's struggles, not only with the Empress but her inner struggles over her own beliefs regarding violence and fighting.
I don't want to spoil the book and reveal the story or the ending but if you've read 'Knife' and 'Rebel' this is a good continuation and the story seems to finish in a way that could suitably end a trilogy. Definitely worth a read if you've read the other books, probably a bit too confusing as a stand alone.