"Gianna knew Santino needed something, anything to keep him safe and entertained. He was well into his 20s, but if he kept going like he had been he'd be dead by 30. So she looked, and asked around, for a new person to fill that rigorous position as his bodyguard.
And she found one."
John is an unrelenting, stoic man, whose godlike fighting skills earned him a very high ranking in New York's assassin world. However, when he gets hired for the bratty brother of Gianna D'Antonio, his entire world comes crashing down.
For better or worse, he's stuck with Santino.