Mary Lennox is 9 years old and lives with her parents in India where her father works for the English government. When her parents die of cholera, Mary is sent to live in a huge mansion with her grumpy, lonely uncle (Colin Firth) and her strict housekeeper (Julie Walters). There the girl will find herself alone in a mansion with more than a hundred doors (most of them closed) and a walled garden where, with the help of fantasy and in the company of her sickly cousin and a young man from the village, they will embark on a wonderful adventure.