Fading Shadows - Savage North Chronicles, #4

Ross and Kat have butted heads since the day they first met-he's gruff, grumpy, and always glaring at her; and she's sarcastic, sassy, and exasperates the hell out of him. But a lot can change in three years, and with a thriving settlement in Whitehorse, Ross and Kat have had to put their differences aside in order to protect their close-knit community. In fact, they've come to need one another more than they realize, until now.
Crazed survivors and Ability-hungry madmen aren't the only repercussions of the Virus, and when a new, unforeseen danger threatens the townspeople, Kat must embrace her unharnessed Ability she's been trying for years to avoid, and just as Ross realizes his feelings for his smart-mouthed partner, it might be too late. Together, Ross and Kat will be tested, and in the grips of fear, they must fight to save those they love and themselves .