By the Book — Hank Edwards

FBI Special Agent Aaron Pearce, tall, muscular, a lone wolf with an attitude, is assigned to protect Mark Beecher, a witness to the plans for a terrorist attack. The discovery of an unknown informant within the FBI's ranks, however, forces the two men to hole up in a loft apartment with only one another for company.
After long conversations and their shared attempt to unravel the puzzle of the terrorist group's next target, Pearce and Mark find they cannot deny their mutual attraction. Pearce gives in to his passion, sleeping with the man he's sworn to protect and going against his training as he risks heartbreak once again.
When the informant reveals himself to Pearce and takes him hostage, Mark finds he cannot run and leave Pearce to die. Instead, their roles have been reversed and now he is the only person who can save Special Agent Pearce.