Jasper isn't human anymore. No one can tell exactly what was done to him by the scientists who captured him, but he's stronger, faster, and a freaking mess.
Frazer is the best person to help Jasper deal with his new reality. He was in Jasper's place once, and now he's a council assassin. They're both human, yet not, and Frazer understands what that's like. The fact that he's attracted to Jasper and wants to climb him like a tree doesn't have anything to do with it.
Really, it doesn't.
Jasper has to face the reality of what having shifter DNA means, especially when he realizes there's a good reason he's so drawn to Frazer. Wrapping his mind around the fact that they're mates is the easy part. The hard one is dealing with his new abilities.
And with the man calling himself a mutant who's outing the labs to the country and trying to pull Jasper into a fight he doesn't want anything to do with.