Fatal Temptation by Ana Night

Akio has lived most of his life as the unwanted son of a sadistic Yakuza boss. His escape included gaining a brother he didn’t know existed, a big family of outlaw bikers, and a fiery crush on the FBI agent who helped them. Lucas is a reluctant family friend and the ex-fiancé of Akio’s new brother-in-law, but that doesn’t stop him from falling hard for the man.
Lucas is a federal agent and a decade older than Akio. He should never have looked at him twice. What started as innocent affection has turned into a desire so deep that he fears it may have fatal consequences for him if he ever gives in. Already walking a fine line at work, he might end up in even more trouble when Akio desperately needs his help, but he’ll do whatever it takes to keep Akio safe.

When they discover a connection between Akio’s former life and the trafficking ring Lucas has been trying to shut down for years, they’re thrust into a high-stakes game of danger and desire, where every move could be their last…