Isabella was a pilot of the human variety (specifically, female) and the proud owner of the Centennial Chihuahua. This youthful pilot was a competitor to the smuggler known as Han Solo.
Isabella was sitting in Chalmun's Spaceport Cantina during 0 BBY when she was approached by two farmboys who were stepbrothers, Phineas Flynn and Ferb Fletcher. These boys had recently acquired a disk containing the schematics for an Imperial battlestation called the Death Star. Flynn told Isabella that they needed a pilot to chase a ship that had just departed from Docking Bay 94, which Isabella recognized as the Millennium Falcon. Isabella then explained her rivalry with Solo to the boys. Upon hearing the Twi'lek singer Vanessa sing a song with the words "so low," Isabella, deciding to accept the job and leave, fired a blaster towards the stage.
Isabella and her companions chased the Millennium Falcon aboard the Centennial Chihuahua. To avoid detection by the Empire, Flynn and Fletcher modified the Chihuahua's deflector shield so that it functioned as a cloaking device. Later, Flynn entrusted Isabella with the Death Star plans to ensure their safe delivery, while he stayed behind to rescue Fletcher.
Isabella delivered the plans to Rebel technicians located on Yavin 4. Despite her initial hesitation to become further involved with the Rebellion, an encounter with Han Solo and Chewbacca changed her mind. Following this, Isabella returned to the Death Star to rescue Flynn and Fletcher.
Isabella was present at the Royal Award Ceremony afterparty on Yavin 4. During this celebration, she kissed Flynn.