Guardians of Time

After a 21st-century bus gets lost in medieval Wales, time-traveling king David must find a way to return the passengers to their own era. A sweeping tale of magic, valor, and romance! --Bookbub on Guardians of Time.
Christmas 1292. Christmas 1292. Bridget knew she didn't look like the type of person who'd do well in the Middle Ages. She didn't have a university education. She couldn't speak French, Welsh, Middle English, or anything in between. But when, for the first time in her life, she listens to her own heart instead of doing what everyone else is telling her to do, and her best friend Peter decides to do the same, suddenly what started out as impulse begins to look a lot like prescience.
And then when things don't go as planned, either in the modern world or the medieval one, it's up to them to alter history and save the Kingdom of Wales ... again.
Complete Series reading order: Daughter of Time, Footsteps in Time, Winds of Time, Prince of Time, Crossroads in Time, Children of Time, Exiles in Time, Castaways in Time, Ashes of Time, Warden of Time, Guardians of Time, Masters of Time, Outpost in Time, Shades of Time, Champions of Time, Refuge in Time, Unbroken in Time, Outcasts in Time, Hidden in Time, Legacy of Time. Also, This Small Corner of Time: The After Cilmeri Series Companion.