Waterfall (The River of Time Series, Bk. 1)

Most American teenagers want a vacation in Italy, but the Bentarrini sisters have spent every summer of their lives with their parents, famed Etruscan scholars, among the romantic hills. In Book One of the River of Time series, Gabi and Lia are stuck among the rubble of medieval castles in rural Tuscany on yet another hot, boring, and dusty archeological site . . . until Gabi places her hand atop a handprint in an ancient tomb and finds herself in fourteenth-century Italy. And worse yet, in the middle of a fierce battle between knights of two opposing forces.