The Bun and the Gun by Vanessa Gray Bartal

Maggie Eldridge’s life as a college reference librarian was simple, predictable, and boring. That was how she liked it, at least until a mysterious stranger showed up with an unbelievable offer. Soon Maggie found herself giving up everything familiar to move cross-country for the chance at an adventure she didn’t know she’d been missing.
Cameron Ridge thrived on discipline. From his early days as a SEAL to his years working undercover, discipline made him an elite warrior. When he was given the task of heading a new team, he knew he needed someone with Maggie’s skill set. What he didn’t count on was how much he would come to need the soft and warm little librarian who force fed him cake and made him laugh.

They formed a friendship from the moment they met, far deeper than either of them could comprehend. Why did they feel so comfortable with each other? How was it possible to have such a perfect friendship with no hints of romance? And why did everyone insist on viewing them as a couple when they were clearly just friends?
When a ghost from Maggie’s past reappears and threatens everything, Maggie and Ridge will have to go to unexpected lengths to save the world. In the process, they might discover that sometimes the best things in life are hiding in plain sight.