Professor Hayashi inhabits a future world of hovercars and advanced technology. He grows convinced of an imminent invasion by insectoid aliens—the Devil Seijin from Planet Devil—but faces widespread ridicule and dismissal from both the scientific community and the public for his warnings.

His technological skill and compassion emerge following an alien attack. Targeted for elimination by the Devil Seijin's explosive cactus-like bombs, he and his young son Tsutomu are shielded during the assault by four stray dogs befriended by Tsutomu: Queen, Ace, Jack, and Joker. The dogs perish saving them.

Harnessing his scientific expertise, Hayashi retrieves the dogs' surviving brain matter and reconstructs their bodies as advanced cyborgs. He equips each with specialized combat functions: Queen gains an energy reservoir system and a cranial drill; Ace receives enhanced optical functions including night vision, X-ray vision, and a plasma gun; Jack is fitted with a "Jet Guster" mouth mechanism generating vortexes; Joker obtains a plastic body enabling shape-shifting. Crucially, all four cyborg dogs retain their loyalty and emotional bond to Tsutomu.

Hayashi further designs the cyborg dogs with a transformative function, enabling them to combine into a unified spacecraft named Liner. This vessel possesses offensive systems like a nose-mounted tracking beam and ramming capability. It can also separate into smaller individual fighter jets designated Battle Formation N.2, serving as the primary weapon against the alien threat.

After creating the cyborg dogs, Hayashi continues his fight against the Devil Seijin. He is subsequently killed by the aliens during their escalated invasion, before their plan to destroy Earth by detonating bombs implanted on the Moon reaches its final stage. His scientific legacy—the cyborg dogs and the Liner—passes to Tsutomu, who assumes responsibility for confronting the alien menace.