Mary Lennox, a sickly ten year old girl, adrift in the world after both her mother and father die is sent to Yorkshire to live with an uncle whom she has never met, at his isolated house, Misselthwaite Manor. Initially Mary is seen as a rude, aggressive and selfish child. She dislikes her new home and the people living in it. But now the scene is set for her transformation and the introduction of the author's engaging theme of rejuvenation and renewal. In exploring the grounds Mary finds the key to the locked garden which is neglected and overrun with weeds. She sets her mind to bringing it back to life. In doing so, Mary finds a purpose and an excitement in her lonely existence. However, apart from the garden, there are other secrets to be revealed at Misselthwaite Manor such as the strange cries in the night and the identity of Colin, a disabled boy, whom she discovers in the hidden bedroom.
The popularity of this novel bears witness to its universal appeal and its timeless hold on the imagination.