Nell is a girl who's been brought up in an isolated world. The only person she knew was her mother and twin sister. They lived together in a cottage in the forest. Nobody has ever met Nell. After her mother's death, she's discovered by the local doctor Jerome. He's fascinated by her, since she speaks an mangled language, developed by her sister and herself growing up; "twin speak" if you will. But Paula, a psychology student, wants her observed in a laboratory. The judge decides they get three months to observe her in the forest, after which he'll decide about Nells future.
Nell is raised in the remote backwoods of North Carolina, never having met anyone except her mother and twin sister. When her mother finally dies, Nell must confront the outside world. Due to her isolation Nell never learned proper English, only a mangled form created by her sister and herself; a kind of "twin speak", if you will. Nice country doctor Jerome Lovell wants to help Nell adjust in her own protected surroundings, while psychology student Paula Olsen and her heartless boss Alexander Paley want to study this rare 'wild child' in their laboratory. But how long can Nell's world remain isolated?