Julie Braun is an eleven-year-old girl from Austria's Southern Tyrol, raised in a rural mountain setting. Her parents, traditional Austrian farmers, perish in an air raid during a family picnic near the end of World War I, leaving her orphaned.

Following this tragedy, Julie moves to Vienna to live with her uncle Karl Clement, his wife Clara, and their children Tina (or Tanya), Heinrich, and Johann. The shift from rural mountains to urban Vienna proves difficult. Julie struggles to adapt to the city and her new household. Cousin Johann initially resents her presence, seeing her as a financial strain, though his resentment eventually thaws.

Julie encounters significant hardship in Vienna. Uncle Karl loses his job at a glass factory, plunging the family into poverty. At school, she faces relentless bullying from classmate Caroline. This animosity stems from Julie's first day, when Heinrich put a frog in her bag; the frog later jumped onto Caroline, causing embarrassment. Caroline's hostility escalates into a fierce rivalry after Julie wins the coveted lead singer position in the St. Charles Cathedral choir. Caroline and her father attempt to organize a performance boycott against Julie, which fails. Caroline later sets a trap meant to injure Julie before a major concert, but ends up caught in it herself.

Despite these adversities, Julie preserves her resilient and cheerful nature, gradually winning over classmates and family. Her deep Tyrolean roots show in her skilled singing of traditional Austrian folk and classical songs—a talent that sets her apart in Vienna. This gift becomes central to her identity and community integration, especially through her choir role.

Julie navigates a complex emotional journey about belonging. She grapples with being a "Child of Two Worlds," torn between her rural heritage and her emerging urban life. This inner conflict sharpens when a friend of her father visits Vienna and remarks, "Julie is no longer Julie of Tyrol," noting her assimilation. Concurrently, her relationship with Alan, a respected classmate, shifts from initial irritation to mutual affection, aided by his understanding of her traumatic past. His parents approve of their budding romance.

Julie finds solace in her pet squirrel, Pepe, and steady support from her aunt and uncle, who assure her they won't send her away despite financial woes. By the series' end, she resolves her inner conflict, choosing to embrace life in Vienna and is described as having become a "true Viennese child."