"Alpha & Omega" is a short story by Patricia Briggs set in the world of her Mercy Thompson series. While it is certainly not necessary to read Briggs' Mercy series, "Alpha & Omega" will be richer if you do. The two main characters are Charles Cornick (Samuel's brother & Bran's son) & a new werewolf, Anna Latham. Charles instantly recognizes Anna as his mate & an Omega wolf. The Omega wolf was a new concept to me & is a wolf who is outside of the pack structure & provides a calming influence to, among other things, wolves who have trouble with the change.