Exiles in Time (The After Cilmeri Series)

Two years in Afghanistan; four years working for MI-5, the British security service; and the death of both of his parents from cancer. At the age of thirty-four, Callum thought he'd experienced the worst that life could throw at him. That is, until his boss ordered him to open a buried file on his desk and to take it seriously. His new assignment: to detain and question a pregnant woman and her ailing husband--and if need be, to stop them from returning to medieval Wales.

Until today, Callum believed in his job and always followed orders. Until today, he thought time travel wasn't real ...