The story begins with a journey on a stagecoach that carries young Rebecca Rowena Randall from the remote Sunnybrook Farm to the austere brick house of her maiden aunts, Miranda and Jane Sawyer. While Miranda is stern, exacting, and continually critical of the child's imaginative nature, the gentler aunt Jane provides a quiet harbor of warmth and understanding. Rebecca's arrival in Riverboro marks the beginning of a transformation, as her vivid mind and natural cheerfulness touch the lives of everyone she meets, from her loyal friend Emma Jane to the lonely villagers.
Life in the brick house is a daily exercise in patience and duty for Rebecca. She attends the local school taught by Miss Dearborn, where her quick wit and unconventional ways constantly startle her teachers and classmates. Despite frequent clashes with her aunt Miranda's strict standards—often resulting in humorous or tearful penances—Rebecca continues to grow in wisdom and character. She forms deep attachments, brings joy to an elderly couple nearby, and proves her capability during moments of unexpected crisis.
Years pass, and Rebecca blossoms into a bright, ambitious young woman determined to earn her own living and eventually help lift the heavy mortgage from her family's farm. Her literary talents and warm spirit draw the admiration of a generous benefactor, Mr. Aladdin, whose quiet kindness helps pave the way toward her future education at Wareham. Through struggles and triumphs, the girl from Sunnybrook Farm retains her poetic soul, learning that life's difficulties are merely stepping stones toward grace and maturity.