Hello Beautiful by Ann Napolitano revolves around the lives of four sisters and William Waters. The plot opens in 1960, where William's story begins. He loses his sister shortly after his birth, and his parents become emotionally distant from him. The mental health of William deteriorates as a result of growing up in such a household. However, after discovering his passion for basketball, he starts opening up to others, though without forming deep emotional connections. William gets admitted to Northwestern University on a sports scholarship and meets Julia Padavano. They soon start dating.
Julia lives with her parents and three sisters: Cecelia, Emmeline, and Sylvie. Due to the closeness of their family, William finds it strange since he has never encountered something like this before. Gradually, he becomes a part of the Padavano family. Just as William's life starts improving, he gets into an accident during a match and injures his knees, ending his basketball career. He falls into depression, but with Julia's support and care, he overcomes his hurdles and decides to become a history professor, finding a new purpose in life.
Amidst these problems, another issue arises in the Padavano family when they discover Cecelia's pregnancy. Her mother disowns Cecelia for deciding to be a single parent and kicks her out of the house. Trying to correct the situation, Julia marries William and decides to start a family. Meanwhile, Rose, Julia's mother, moves to Florida, and Sylvie becomes homeless, ending up living with Julia. William's mental problems worsen, but Julia becomes busy working and caring for their baby, Alice. Sylvie, on the other hand, worries about him. After William leaves the house, he tries to commit suicide, but a passerby saves him. Sylvie visits him in the hospital and realizes her love for him. Eventually, William finds the courage to express his feelings to her. Afterward, Julia demands a divorce for the sake of Alice. Julia moves to New York and lives a happy life until she learns about the relationship between William and Sylvie. She cuts off all contact with them and tells Alice that her father died when she was a baby.
A few years later, Julia remains involved with her family, but Alice is curious about her father. One day, Julia receives a call from William, who requests her to meet Sylvie because she is dying from a terminal brain tumor. Julia and her sisters reconcile and try to forgive each other's wrongdoings to live their lives free of burden. In the end, Julia decides to reveal the truth to Alice about her father so there will be no regrets.
