Lauren Smith 
The Darkest Hour: The Surrender Series – Book 4 [EPUB ebook] 

Royce Devereaux isn’t your average sexy professor. He has a lot of rules in his professional and personal life. He keeps both worlds separated. He has to. He’s somewhat of a public figure—and yes, he’s made enemies climbing to the top. Being a world-famous paleontology professor doesn’t mix well with his romantic life. He likes his sex rough, and a whole lot of naughty. Which means his students are 100% off limits. 

 One problem. His new graduate student assistant, Kenzie. She looks at him like a kid looks at birthday cake, and he doesn’t like it. Except, he does. He likes it too much. She’s feisty and smart—which only makes him want to tie her up and master her body. And her buttoned-up librarian look—it makes him want to strip her naked…slowly. He has to find a way to ignore her. It’s only one semester. Right?

 But when an enemy decides to use Kenzie to force his hand, Royce has no choice but to keep her close. Very, very close. His two worlds have just collided. He just hopes he can let her go once the danger is over…