The Travelling Strangers (Outlander//Merlin Crossover)

1945: A history student follows Claire to the Standing Stones at Graigh na Dun to stop her from going through. By accident she takes Claire's place and travels through time to find herself in the year 1743. Here she encounters several threats, but gets unexpected help from the young Scot Jamie Fraser.

Meanwhile, though years and years before, Merlin and Arthur are dealing with difficulties of their own. To help them, future Emrys (Merlin) sends his pupil Annabel through the Stones to Camelot, where she immediately befriends them. Arthur quickly falls for her, and when Merlin gets poisoned, they go on an adventure together to get a cure. There's only one problem: Annabel carries a secret with her that could change everything.

When things escalate, Manon and Annabel learn that their fates are intertwined, and discover that every choice has a consequence.