Isabella appears during the Spanish Grand Prix story arc, meeting Takaya Todoroki during his travels. Their interactions occur primarily at the Jarama circuit, where she challenges him amidst his competitive difficulties. She belongs to a family with bullfighting connections. Her brother, a bullfighter, died in a racing-related incident, fueling a desire for revenge within the family, particularly from another brother named Jida. Her wealthy father proposes marriage to Takaya following the bullfighter brother's death, intending to make him heir to the family fortune. This offer coincides with Takaya's period of discouragement after racing setbacks.

A significant conflict arises when Jida, seeking vengeance, orchestrates a dangerous trap targeting Takaya during preparations for the 24 Hours of Le Mans. Isabella intervenes to warn Takaya, sacrificing herself to prevent him from triggering the trap. This act results in her sustaining critical injuries. Hospitalized in desperate condition, her survival requires blood transfusions from both her father and Takaya. Despite her critical state, she urges Takaya to compete in the Le Mans race, prioritizing his racing dreams over his presence at her bedside. Jida, realizing the consequences of his actions, despairs and ultimately falls victim to his own trap. Takaya proceeds to race and wins, fulfilling Isabella's wish, but she dies from her injuries.

Her death profoundly impacts Takaya. He dedicates his subsequent victory in the French Grand Prix to her memory. Her legacy continues to influence him later in the series when her mother, blaming Takaya for the deaths of Isabella and her brother, attempts to have him killed.