In this final book of Bergren's River of Time trilogy (Waterfall, Cascade), doughty heroine Gabriella returns through the time tunnel to 14th-century Italy with her sister, Evangelia, her mother, and, on this trip, her father, hoping to undo his accidental 21st-century death. Gabi's heart is in the past. She reunites with Lord Marcello Fiorelli, a handsome prince of his city-state. Although 15 months have elapsed since Marcello has seen Gabi, they reaffirm their love, but warring between Siena and Florence pushes aside romance. Gabi hurls herself and her family into a series of well-described, harrowing adventures. Her almost preternatural psychological and physical strength strains credulity, but Bergren provides glimpses into the 21st-century adolescent mind with bits of dialogue between the sisters and snippets of Gabi's thoughts, the teen's modern slang jarring intentionally with the more formal language used by medieval characters. The action precludes exploring the nuances of the Betarrini family's situation, so the resolution of their dilemma--will they choose past or present?--lacks emotional resonance. The ending, however, provides a romantic answer that should satisfy and perhaps surprise Bergren's fans. Ages 12up. (Sept.) Copyright 2011 Reed Business Information.