Archibald Craven, uncle to Mary Lennox and master of Yorkshire's sprawling Misselthwaite Manor, succumbs to consuming grief and guilt after his wife Lilias dies in a garden accident while pregnant. He seals the garden permanently, a stark monument to his loss. Associating his son Colin with Lilias's death fuels resentment, leading to emotional neglect and avoidance. Archibald retreats into isolation, dwelling in seclusion or traveling abroad, allowing the manor and its garden to decay. His grief physically manifests as a hunched back, which he perceives as a curse and hides beneath his clothing.

His despair deepens when former employee Maximilian Hawkins orchestrates the ruin of his failing business ventures, pushing Archibald toward financial collapse and the potential loss of Misselthwaite. Overwhelmed by hopelessness, he arranges care for Mary and Colin. Confronting a portrait of Lilias, he attempts suicide with a firearm but halts at the last moment, witnessed by Hawkins and Camila, a Romani woman and friend of Lilias. Their forgiveness and concern for the children trigger profound emotional release; tears of relief mark his commitment to change.

Archibald's transformation begins through persistent efforts by Mary, Colin, and Dickon Sowerby. Initially stern and distant, he gradually responds to their engagement. As Mary and Colin, aided by Dickon, restore the secret garden—a symbol of renewal—Archibald confronts his past. He physically participates in the garden's revival. Concurrently, he reconciles with Colin, overcoming resentment and neglect. This reconciliation renews his purpose and familial bonds. His journey concludes with dedication to maintaining the garden and fostering a hopeful future, embodying redemption and healing.