I read this book a year or two ago. It was set in modern day; I believe that it started out with a man driving his car in the desert in the middle of the night. He witnesses a space vessel either crash-land or crashed his own car. (Not too sure on that part.)
He then stumbles upon a battle where an alien man and woman are fighting at the base of the craft and he hears a cricket-like noise. The noise is actually an attack by another group of aliens, but his being human gave him an immunity to the cricket noise. (This noise was known throughout the space travelling galaxy as completely incapacitating their enemies.)
I want to say that the attackers were little grey men. (I think the author may have been alluding to what we associate as the Roswell aliens.)
The man saves the two humanoid aliens from this attack and finds out that the woman is some sort of intergalactic heir to the throne. The other humanoid alien was some type of spouse/guard for the woman, and he ultimately dies from the wounds that are suffered in the battle.
The protagonist ends up on the ship and they return to space.