A young man named Shirokiba Ouga leaves his small island home of Mukurojima, located southwest of Kagoshima, to pursue his dream of becoming a professional wrestler in Tokyo. His love for wrestling began in elementary school when he discovered a VHS tape of old matches in his father's office. Despite feeling responsible for his widowed mother and four younger siblings, his family encourages him to chase his ambition. After five years of sacrifice and training, he achieves his goal, becoming a world champion known as Shirokiba the Hellhound. He returns to his hometown in 2028 to finally show his family his championship belt.

Upon arrival, Shirokiba finds Mukurojima completely deserted and in a state of ruin. Overturned cars litter the streets, communication lines are dead, and an eerie silence hangs over everything. Before he can process the situation, a mysterious alien attacks, decapitating his traveling companion. Shirokiba is forced to fight for his life against this bizarre, grasshopper-like extraterrestrial, using every pro-wrestling technique he knows, from clotheslines to his signature G.T.H. (Go To Hell) Suplex. Although he defeats the creature, a deadly tentacle emerges from its corpse and pierces his chest, leaving behind an alien parasite inside his body. This parasite grants him enhanced strength and accelerated healing, a power he quickly accepts as a necessary tool to save his missing family.

The initial narrative arcs focus on Shirokiba's journey through the occupied island. After being saved by a ten-year-old boy named Haruya, he learns the aliens invaded three months prior, cutting the island off from the outside world and capturing the townspeople in strange pods. Shirokiba, Haruya, and Haruya's recently rescued older brother Tatsumi form an unlikely team. Together, they battle various alien species, including a building-climbing giant and flying pterodactyl-like creatures. The story follows their efforts to reach the bathhouse where Shirokiba's sister, Yuki, is held prisoner, with Tatsumi's hunting skills with a slingshot proving a crucial complement to Shirokiba's raw power.

As the narrative progresses, the alien threat evolves, forcing the characters into increasingly difficult situations. After Tatsumi is grievously wounded by a powerful new alien, Shirokiba conceives a radical solution: to defeat the creature and implant its parasite into his dying friend, potentially turning them both into superhuman alien fighters. The manga explores the growing bond between the wrestler and the hunter as they form a dynamic tag-team to combat the invasion, while also raising questions about the true cost and long-term consequences of accepting alien power to survive. The series is noted for its high-octane action sequences, a nostalgic art style blending classic and modern shonen influences, and a straightforward plot driven by a protagonist who solves problems with wrestling moves.