I'll be happy to narrate the story of Mary Poppins in a detailed, linear fashion:

The story begins in London during the Edwardian era, focusing on the Banks family who live at 17 Cherry Tree Lane. George Banks is a strict, emotionally distant banker, while his wife Winifred is a suffragette more interested in political causes. Their two children, Jane and Michael, are in desperate need of a nanny, as they have repeatedly driven away previous caretakers with their mischievous behavior.

One day, after the children write their own advertisement for a perfect nanny, the magical Mary Poppins literally descends from the sky, carried by the wind. She arrives at the Banks household and immediately interviews with Mr. Banks, impressing him with her precise and proper demeanor. Despite her unconventional entrance, she is hired on the spot.

Mary quickly transforms the children's lives with her magical approach to childcare. She takes Jane and Michael on extraordinary adventures that blend imagination with reality. In one memorable sequence, they jump into a sidewalk chalk drawing, entering a vibrant animated world where they have a delightful day with Bert, a charming street artist and jack-of-all-trades.

Throughout these adventures, Mary teaches the children important life lessons about imagination, kindness, and looking beyond the mundane. Her magical abilities - like bottomless carpet bags and the ability to make cleaning a fun game - enchant the children and gradually begin to soften the household's rigid atmosphere.

A key character in the story is Bert, played by Dick Van Dyke, who serves as a narrator and friend to Mary. He helps bridge the magical and real worlds, often appearing in different roles throughout the children's adventures.

The dramatic core of the story revolves around Mr. Banks' emotional journey. Initially a stern, work-obsessed banker who values order and discipline above all, he gradually learns to reconnect with his children and understand the importance of family over professional strictness.

A pivotal moment occurs when Mr. Banks is called to the bank, where he is expected to be fired for a supposed professional mistake. This moment becomes a turning point for his character, forcing him to reevaluate his priorities and understand what truly matters in life.

The film culminates with the Banks family becoming closer, with Mr. Banks learning to be a more attentive and loving father. Mary Poppins, having accomplished her mission of healing the family, decides it's time to leave, carried away by the wind just as mysteriously as she arrived.

The movie is filled with memorable musical numbers that advance the story and reveal character emotions, including "A Spoonful of Sugar", "Supercalifragilisticexpialidocious", and "Chim Chim Cher-ee".

Ultimately, Mary Poppins is a magical tale about the importance of family, imagination, and emotional connection, told through a delightful blend of live-action and animation, with memorable performances and iconic music.

Short Narrative Ending: In the end of "Mary Poppins," the Banks family, having gone through a transformative journey with Mary Poppins, realizes the importance of family and joy. After a magical day filled with adventure, the wind (symbolizing change) shifts, and Mary Poppins prepares to leave. The family comes together, and Mr. Banks finally understands the value of treasuring moments with his children. As Mary Poppins departs, she floats away with her umbrella, leaving the family united and happier than before.

Expanded Narrative Ending: As the film "Mary Poppins" reaches its conclusion, everything culminates during a delightful yet poignant scene in the Banks household. After an enchanting adventure filled with laughter, magic, and whimsical experiences, Mary Poppins realizes it's time for her journey to come to an end. The wind, a recurring theme throughout the film symbolizing change, picks up, signaling her departure.

Mr. Banks, who has been consumed by his job and societal expectations, arrives home to find his children full of joy from their recent adventures with Mary. He watches them play and begins to understand that their happiness is far more important than his rigid adherence to work. More importantly, he learns to appreciate the moments that matter with his children, instead of dismissing them as distractions.

As Mary Poppins prepares to leave, the family gathers to bid her farewell. The final moments are bittersweet; although they are sad to see her go, they have been profoundly changed by her presence. Mary, with her magical umbrella, takes off into the sky, embodying the themes of love and cherishing familial bonds. The story closes with Mr. Banks finally understanding that being present for his children and finding joy in the small things is crucial. This transformation not only strengthens the family unit but also emphasizes the importance of balance in one's life--between work and familial responsibilities.

In summarizing the ending, it's significant to note that the key takeaway here is the value of embracing joy and connection within a family. The story beautifully conveys that true happiness stems from love and unity, highlighting the need for parents to prioritize relationships with their children over societal pressures and expectations. This lesson resonates with viewers, reminding them of the importance of balance and the magic that can come from simply being together.