Hiro Takagi, a corporate survey team member aboard a deep-space cruiser, masquerades as a Japanese division employee while concealing his true identity as a medical student driven by a vengeful mission. His sister’s fatal overdose spurred him to execute three drug dealers he blamed for her death, evading legal systems to deliver his own justice. This vendetta intersects with the crew’s crisis when a hostile alien organism breaches the ship, triggering chaos.

His clandestine past collides with detective Dick Berry, whose stalled investigation into the same drug network—derailed by Hiro’s vigilantism—cost Berry a promotion and fuels their mutual hostility. As the alien threat escalates, Hiro’s inadvertent display of medical expertise exposes his understanding of the organism’s adaptive mimicry and rapid evolution, unraveling his fabricated credentials. Confronted by Berry, he is restrained but remains pivotal to the crew’s survival strategies.

Haunted by guilt, Hiro seeks redemption through suicide, halted by the captain’s timely intervention with an escape plan. Surviving the cruiser’s destruction, he escapes to a nearby planet with survivor Nancy, his path toward atonement tentatively open yet unresolved. Across sources, his name occasionally appears as “Jiro Takagi,” though this discrepancy does not alter his backstory or narrative role.