Little Mary is an orphan, come from India to her relatives in England. Her cousin Colin is a sickly lad, living in the same large cold house that Mary has been sent to. Both children are self-centered and lonely, unhappy in different ways. It is only when Mary finds a rusty old key that opens the long-hidden garden that the two learn to find love and happiness. In the mystery and beauty of nature and living things, Mary and Colin overcome their problems...

Relates the fortunes of three adopted sisters who take dancing and stage training, one to become an actress, the second a ballerina, and the third an aviatrix.

Tom finds himself in the midst of a strange adventure involving a garden that appears only at night and a girl from another time.