The beginning of this takes place in Colonial India, around 1906. The story then moves to Misselthwaite Manor, North Yorkshire, England.
In this play a young girl, Mary, is abandoned by a plague that has killed her family and her friends. She finds herself in England where her newfound uncle will take care of her. The house that she will now live in has been said to be haunted. As any curious young child would do, she wanders around the house until she finds what she is looking for: Colin, a young, ghostly looking boy that seems to be sick. She invites him to come outside and play with her, but he replies no because he is going to die. .
While this young boy stays in bed and waits for his death, Mary finds a garden that has been kept a secret for a very long time. Soon she finds out that the garden was once her deceased aunts and has been kept locked by orders of her uncle. In the garden, Mary finds a friend that also would like to get into the secret garden. They soon locate the key and begin to work on getting it looking beautiful again.
Her uncle leaves for Paris to get away from his problem that haunts him. In the mean time, her uncle's brother, who happens to be the young boys doctor, may send Mary away to school. He feels that Mary is going to kill Colin if she interrupts his recovery by having him to active.
Mary disagrees and writes a letter asking her uncle who has left for Paris to return. Upon his return, the gardens were in full bloom, and Mary also surprises him by Colin's surprising recovery. In the end, the uncle is no longer haunted by his past and everyone seems to be happy. .
Lily - Mary's aunt, also Archibald Craven's wife, who is now dead.
Mary Lennox - a ten-year-old girl.
Mrs. Medlock - Mr. Craven's housekeeper.
Dr. Neville Craven - Mr. Craven's brother, also Colin's doctor.
Archibald Craven - Mary's uncle, and lord Misselthwaite Manor.
Ben Weatherstaff - Dickon Martha's brother, also Mary's friend in the garden.