There is a mystery, and Sam, one of the main characters, is investigating, but even if the mystery plot is a huge and important connector for all people involved in the story, it's not stealing the scene to the romance between Sam and Mac. At first glance you would say Mac has to be the macho man of the story; true it's Sam who has the dangerous and dark career, an FBI agent, but he is more the nerdy type, the one who got in more for his brain than is body strenght (as it has to be in those agencies); wherelse Mac has this puppy attitude, like a big, goofy labrador, who doesn't want anything else but be loved, you can really do big damage to this man if you don't treat him well, since he is open and big heart.
As Sam well highlights, while it seems that Mac is letting Sam leading their relationship, he is actually topping him from the bottom, managing to obtain everything he wants just being open and willing with his love, Sam has no courage to disappoint the man.
I'm pretty sure I will have to read book 2 in the series soon, since these characters go beneath your skin, and you would want to know more about them, their lives and the realization of their dreams.
Amazon: Six Degrees of Lust
Amazon Kindle: Six Degrees of Lust
Paperback: 392 pages
Publisher: MLR Press (December 27, 2011)
Reading List: http://www.librarything.com/catalog_bott