Prince of the Brotherhood by K. Alex Walker

She’s a spy.
He’s her target.

The day intelligence operative, Eija Barrett, stepped foot inside Interpol headquarters, she’s had one main objective—infiltrate and dismantle the largest sect of the Russian Mafia, run by the renowned Yuri Sokolov, based in Moscow.
Each attempt by the agency, so far, has failed.
But Eija then discovers that the mafia leader has been hiding something she can use to her advantage—a son who Yuri has kept secret since birth, and who is next in line to head the crime syndicate.
Dominik Sokolov.
Eija knows if she can get to Dominik, she can get to Yuri and, as far as she’s concerned, there’s nothing that can stand in the way of that happening…
Only a handful of people know what Dominik Sokolov looks like, and even fewer know who he really is. However, as the mysterious Prince of the Brotherhood and the only son of mafia leader, Yuri Sokolov, it’s Dom’s birthright to lead the organization.
His duty.
Dom is able to spend three months on the island of Grenada, off-the-grid and away from the family’s watchful eye, but when Yuri finds him there, he decides it’s time to head home. Before he leaves, he meets a beautiful woman whose name he learns by accident—Eija. He tells her his name is Andrei…not that it matters. Not that it will make a difference, to her, who he is.
After all, once they’ve had a few nights of fun on the island…the two of them will never see each other again.