In this chapter, Mary Lennox continues to explore the grounds of Misselthwaite Manor, still grappling with her loneliness and the oppressive atmosphere of her new home. As she wanders the estate, she becomes increasingly curious about the tales of the secret garden that she has heard from Martha, the maid. The garden is described as a once-beautiful place that has been locked away for ten years, hidden from sight and neglected. Mary’s desire to uncover this secret garden grows stronger as she learns more about its mystery.

One day, as Mary is roaming the grounds, she encounters a robin. This robin becomes a pivotal character in her journey, as it seems drawn to her and begins to display unusual behavior. The bird appears to recognize Mary’s longing for companionship and adventure, and it starts to lead her around the garden's periphery. Intrigued, Mary follows the robin, which flits from branch to branch, encouraging her to pursue it further into the wilderness surrounding the manor.

The robin’s persistence eventually brings Mary to a hidden door covered in ivy – the entrance to the long-lost garden. Mary is filled with excitement and trepidation as she approaches the door. The robin chirps and flutters about, as if urging her to unlock the door and step inside. Mary, motivated by the bird and her own curiosity, takes out the key she had found in the old house, which she believes might fit into the lock.

As she inserts the key and turns it, she feels a surge of anticipation. The door creaks open, revealing a stunning scene that contrasts sharply with the dreary nature of Misselthwaite Manor. Mary steps into the garden, which is overgrown but still brimming with the potential for beauty and life. She is overwhelmed by the scents of flowers and the sight of wild plants. This moment marks a significant turning point for Mary; the unlocking of the garden symbolizes not just the entry into a physical space, but also the opening of her heart to joy and possibility.

In this lush, vibrant environment, Mary feels a sense of freedom and wonder that she has never experienced before. The robin, having fulfilled its role as a guide, flits away, leaving Mary to explore this magical space on her own. As she begins to take in the sights and sounds of the garden, she senses that this hidden world will play a crucial role in her transformation, setting the stage for the growth and healing that will unfold in the chapters to come.