A savvy street urchin named Casey Brown (Jodie Foster) and an ex-con (Leo McKern) take advantage of an elderly woman, Lady St. Edmund (Helen Hayes), by having Casey pose as her estranged granddaughter. Their aim? To steal a cache of treasure they think she's hiding. But when she moves in, Casey begins to wonder whether their plan has any basis in truth -- and whether she even wants in on the heist anymore.