It's 1914 and Winnie Foster (ALEXIS BLEDEL) is a 15-year-old who feels smothered by her proper, upper class upbringing imposed upon her by her conservative and wealthy parents Augusta (AMY IRVING) and Robert (VICTOR GARBER). She longs for a life outside her fenced-in estate, and thus decides to run away when she learns that she's to be sent off to a strict, all-girls school.
She ends up getting lost in her family's large and heavily wooded lands and then runs into fellow teenager Jesse Tuck (JONATHAN JACKSON) who's drinking from a spring at the base of an old tree. She's surprised by his presence and he's not happy she spotted him. Before either can do anything, however, Jesse's older and stern brother, Miles (SCOTT BAIRSTOW), shows up, grabs her and returns to the family's cabin home.
There, she meets the boys' parents, Angus (WILLIAM HURT) and Mae (SISSY SPACEK), and eventually learns that the spring from which Jesse was drinking has caused the entire family to be immortal and permanently stuck at the age from their first drink.
It's also led to the mysterious Man in the yellow suit (BEN KINGSLEY) who's trailed the brothers back to their home environs. As he attempts to find them and their source of immortality, and Winnie's parents call out the forces to find her, the teen must decide whether to join the Tucks as they try to maintain their secrecy and unique lifestyle.