"The Invisible Circus" covers familiar territory — Sixties radicalism — with unexpected twists. Director Adam Brooks, who adapted the novel by Jennifer Egan, is telling a ghost story. Eighteen-year-old Phoebe O'Connor (Jordana Brewster) is haunted by her sister Faith (Cameron Diaz), a political revolutionary who killed herself in Portugal in 1971. Why? Six years later, Phoebe leaves San Francisco and her widowed mom (Blythe Danner) to find out, retracing Faith's European odyssey. That includes a trip to Paris to catch up with Faith's former lover, Wolf (Christopher Eccleston). Brewster is a talent to watch. And Diaz, seen only in flashbacks, makes Faith a magnetic figure. The script hits rough patches, especially when Phoebe and Wolf get it on, but the sisters cut to the heart.