Caroline?

Adaptation of the novel Father's Arcane Daughter by E. L. Konigsburg. Fourteen years after being presumed dead in a plane crash, a woman reappears—just in time to claim a sizable inheritance from her grandmother. Set in the 1950s, the story centers around Paul Carmichael and his second wife Grace, who have a somewhat peripheral relationship with their two children, 12-year-old Winston and his 10-year-old sister. Enter Caroline—or a woman claiming to be Paul's ""late"" daughter from his first marriage. Paul accepts her story that she never boarded the plane, and used the crash to escape her shallow debutante life. But Grace is more than skeptical, and the headmistress of Caroline's finishing school is quite sure that ""Caroline"" is a fraud.