Time of the Celts — Jane Stain

Jaelle dons a Roman helmet left among her ex's things and is transferred to the Pictish Celt side of Hadrian's wall -- flat on the ground and tripped over by Breth. The naked woad-painted warrior is being chased by Romans who caught him scouting their fort. She earns his trust by grabbing an injured Roman's sword, fighting beside Breth, and saving his life. He takes her to his clan, where she sees druids in their sacred grove imparting magical protection by painting the warriors' nudity with muscle-activated woad pictures.