Family Ties by Susi Hawke

River Erikson is a man on the run. After scenting his true mate, he’s done everything in his power to escape. Just because he was born an omega doesn’t mean he needs to answer fate’s call and drop to his knees for some alpha. Especially not a smug mafioso who thinks way too much of himself. Luckily, his job at STAHP—the vicious vigilante organization that works to police shifters when law enforcement can’t—keeps him busy enough that he can try to forget how his traitorous body reacts whenever a certain muscled Russian is around.
Vasily Novak is stunned when he scents his mate, but powerless to chase him when he flees. How can he? His focus is entirely centered on the precocious five-year-old he recently learned was his child. All he can do is trust the fates to bring his mate back when the time is right. Vasily is confident that River will be his eventually… he just needs to be patient.
When Vasily’s son is taken, River comes to help retrieve the boy who melted his heart the first time Petey called him “pretty kitty.” As the pair leave a bloody trail through the city on their search, will the fates give them a second chance at finding a forever in each other?