This is a Novella on the Origin of Durzo Blint.

Spoiler

Where we see Acaelus Thorne at the lowest moment in his long life. He finally cracks when his latest family is murdered and during the course of the novella, we see Gaelan train to become a Wetboy and become a murderer for hire. During the course of the story, we also see the strain with his relationship with the Ka'Kari as it clearly disapproves of his actions. - which as we all know at this point is why the Ka'Kari abandons him when we get to The Way of Shadows.

We also get a peek at some of the other characters from the trilogy and learn some background info on them.

Although technically a prequel I would recommend reading the Trilogy first before reading this as it does contain massive spoilers for the first book and some of the content in this book can't be truly appreciated without having the prior knowledge of the other books.

Also my copy came with the short story I, Night Angel Which takes place after the events of the third book in the perspective of Kylar.

All in all a fun little read if you enjoyed the Night Angel Trilogy and want to spend more time in this world.