Only the Brave by Rebecca Ruger

Megan West’s Scotland trip is not quite what she was expecting. Three days in and her lost luggage still hasn’t arrived, and she’s already decided her travel buddy, a co-worker she thought would be so easy to vacation with, is actually the most annoying person in the world outside of the hospital. When she stumbles upon a seriously handsome but really strange guy—who carries a sword at his hip!—she decides Scotland is not a good fit for her. If she had luggage, she’d pack it in and call it a day.
Graeme MacQuillan knows the witch from his time purposefully sent him forward to another century, though he isn’t exactly sure why. He strong-arms the first person he meets into helping him find his way home—without telling her the hardly credible truth, that he’s from the 14th century. The bonny lass is justly terrified but helping is in her nature so even though she thinks he’s daft, she’s soon introducing him to all the astonishing sights and sounds of the 21st century.
When Graeme senses a change in the air signifying the coming of witches, he instinctively takes hold of Megan’s hand. He wants to get back to his time, but he’s not ready to leave the beguiling lass behind.
Undeniably, Megan’s vacation just got a lot more interesting. But then her modern life, which she judged as teetering between dull and pathetic, suddenly seems quite preferable to the war and strife into which they’re plunged. Megan is furious with Graeme, who had no right to drag her through time without asking. And now she faces the most important decision of her young life: does she want to return to her own time and never again know the sweet perfection of his kiss? Or is she brave enough to follow the hope in her heart?