Ken Hayabusa's defining tragedy stems from the murder of his older brother by the villainous Black Shadow racing team, fueling his relentless drive throughout the series. This propels him into the Saionji racing team, established specifically to dismantle Black Shadow's corruption of international racing. As Team Saionji's primary driver, he pilots their cutting-edge Falcon vehicle, powered by a hyper-potent Cavalier Engine. The Falcon evolves through successive upgrades—from V1 to V5—each iteration adding rocket engines to amplify speed and power, a necessary response to Black Shadow's increasingly lethal racetracks and superior machinery. These enhancements gradually diminish the relevance of his teammates' cars during races.

Initially, Ken exhibits a volatile, impulsive nature, frequently clashing with team leader Dr. Saionji when his thirst for vengeance overrides strategic objectives. Their relationship remains fractious yet anchored by a shared commitment to destroying Black Shadow. Continuous exposure to the team's perilous challenges and his role as ace driver gradually tempers Ken's rashness, fostering greater emotional maturity and tactical insight.

His personal bonds include a deepening romantic connection with Sakura Saionji, Dr. Saionji's sister, whose steadfast support bolsters him during races. He also maintains a complex partnership with Dr. Saionji—marked by friction but unified by purpose. Ken carries a photo of his slain father and brother, a constant reminder of his mission.

The climax unveils Black Shadow's leader, Ahab Mobil Dick, as Benny Kramer—the direct killer of Ken's brother. This revelation ignites Ken's resolve just before their final showdown. Though he triumphs over Black Shadow, securing the championship and thwarting their schemes, Kramer escapes justice, leaving Ken's quest fulfilled yet bittersweet.