The Fall of Promise by T. S. Joyce

Daylen Hoda is a wicked wolf.
He’s done the unforgiveable at his Alpha’s order, and now he must face the life he used to have. Coming home should feel like a comfort, but Daylen isn’t the same werewolf anymore. Two years ago, he was pulled away from his Colorado territory by his Pack, and he left someone important behind. Denver has been his best friend and safe place for as long as he can remember, but he knows exactly how she will react if she finds out what he’s done. She can’t find out. She can’t know. She can’t realize what a monster he’s become, or he will lose the only thing that makes sense. The Pack is falling apart, his Alpha is retiring and he’s up next to lead the werewolves in this territory. Daylen isn’t sure of much anymore, but this he knows—he isn’t ready to be the Alpha. Not until he fixes all the things he’s broken, including his friendship with Denver. The problem with that? She’s not the same girl he left behind anymore.

Denver Mosely is a loyal fox.
Two long years have passed since her best friend, Daylen, left the territory without an explanation, and when he blows back into town unexpectedly, he’s unfamiliar. His wolf side isn’t acting right, the man in him has changed, and he’s doing his best to avoid her. But why? She was here in his territory, making sure his den was taken care of, and waiting for the day she would get some answers to his disappearance. New Daylen doesn’t give any answers, and it’s up to Denver to pry his recent past from him. What can be so bad that a man hides this thoroughly for so long? New Daylen is edgier, darker, very handsome and has a new set of scars on his outsides and insides that draw Denver’s attention, and stirs up feelings she’s never had for her friend before.