In 1810s London, teenaged Mary Godwin (Elle Fanning) began a scandalous romance with her philosopher father's young-and married-acolyte, the poet Percy Bysshe Shelley (Douglas Booth). The years they spent in flight from England in the company of her free-spirited stepsister Claire Clairmont (Bel Powley)-including the fateful visit to the Swiss retreat of Lord Byron (Tom Sturridge) that inspired "Frankenstein"-are chronicled in this memorable effort. Stephen Dillane, Joanne Froggatt co-star. 121 min. Widescreen; Soundtrack: English.