One-Punch Man: Season 1

A monster named Vaccine Man wreaks havoc in a city and is about to kill a young girl when a bald hero named Saitama intervenes and kills him with a single punch. Saitama recalls the events three years earlier that pushed him to become a hero; after saving a boy with a cleft-chin from Crablante, Saitama resolved to become a hero but became too powerful for his own satisfaction. Following taking out the Brain and Brawn Brothers, one of whom is a mutated giant, Saitama has a dream about a subterran

A cyborg named Genos tracks down a mutant called Mosquito Girl, whose mosquito swarm drains the blood out of everyone they come across within the city. Genos has a difficult time with Mosquito Girl who almost forces him to activate his self-destruct as a last resort to stop her. Saitama then suddenly stumbles into the fight, easily defeating Mosquito Girl. Genos tells Saitama how a mad cyborg destroyed his hometown and killed his family. Despite Genos's extremely boring explanation of his past,

Armored Gorilla tells the story of Doctor Genus, the House of Evolution's founding leader who wants to study Saitama's power to replicate it. Saitama and Genos reach the House of Evolution's base, forcing Genus to release his strongest creation: the unstable Carnage Kabuto. After Kabuto effortlessly defeats Genos, Saitama is eager to fight him, but Kabuto cowers upon sensing Saitama's limitless power. Saitama finally explains the secret to his strength-a simple workout regimen, much to Genos and

The hard-headed criminal Hammerhead forms the Paradisers terrorist cell to demand free goods for the unemployed, targeting local business magnate Zeniru using stolen enhancement suits. While they easily defeat bicycle hero Mumen Rider, Hammerhead's men are taken out by Zeniru's hired ninja Speed-o'-Sound Sonic. Hammerhead flees after surviving a kunai stab to the back of his head, only to run into Saitama, who clarifies his lack of association with the Paradisers despite their shared baldness. S

Saitama and Genos pass an exam for the Hero Association, with Genos placing in S-Class while Saitama ends up in C-Class by breaking every record in the physical portion of the exam but doing very poorly in the non-physical sections. They then attend an orientation seminar by Snakebite Snek, who is annoyed that Saitama does not pay attention to him. Snek tries to newbie crush Saitama, but is humbled when Saitama effortlessly defeats him. Having received new upgrades, Genos asks Saitama to spar wi

Saitama tries to come up with ideas for mentoring Genos, then rushes off to find a villain once learning that C-class heroes get dropped off the registry after a week of inactivity. Sonic demands to settle their alleged rivalry, but Saitama refuses. Tank-Top Tiger reproaches Saitama for his antics and tries to steal credit when Sonic attacks him for interfering between him and Saitama’s rivalry. Sonic then starts causing mayhem to force Saitama to fight him; Saitama indeed notices, and swiftly k

Scientists discover a meteorite suddenly changing course toward City Z, prompting the Hero Association to deploy all S-Class heroes. Genos is the first to arrive, followed by veteran hero Bang, who warns that evacuations are underway and urges him to leave. Bang refuses to abandon the city, but before introducing himself further, Genos rushes into action. Soon, Metal Knight arrives, intent on testing his weapons rather than cooperating. His assault fails, and Genos' own prototype weapon, though

The Seafolk Tribe declare war on humanity. On his way home, Saitama casually kills an octopus-like monster, while Mumen Rider arrives too late, finding only the remains and hearing bystanders discuss Saitama. Curious, Mumen researches him online, discovering his strength but also the divided opinions surrounding him. At City J's coast, massive Sea-Folk emerge, prompting Class A hero Stinger (Rank 11) to challenge them with his Bamboo Shoot weapon. Though he defeats several foes, their leader the

Genos engages the Deep Sea King and initially overpowers him, but the monster tears his arm off. Genos urges civilians to flee before shielding a child from an acid attack, suffering severe damage. At that moment, Mumen Rider arrives. Though hopelessly outmatched, his determination inspires civilians. He repeatedly charges the Sea King, only to be beaten down brutally. Just before the final blow, Saitama arrives and catches him. After a brief exchange, Saitama defeats the Deep Sea King with one

The Ancient King of the Terror Lizard Clan appears but is instantly defeated by Tatsumaki. At his dojo, Bang tells Saitama and Genos about his rogue disciple, Garou, who defeated all of Bang's top students. Suddenly, a Hero Association messenger arrives, declaring an emergency and summoning all S-Class heroes. At headquarters, Saitama meets several S-Class heroes. Only Blast and Metal Knight are absent. Sitch, a staff member, announces that the great seer Madame Shibabawa has died during a predi

Geryuganshoop laments Groribas' defeat, noting only he and Melzargard remain as Boros' elite fighters. He warns Boros that the ship is being ravaged by a human intruder. Outside, Melzargard regenerates endlessly against Puri-Puri Prisoner's attacks, then sends one head to request aid from the ship, only for Metal Bat to smash it down. Atomic Samurai, Bang, and Puri-Puri Prisoner combine forces against him. While Melzargard telepathically requests a cleansing bombardment from Geryuganshoop, Metal

Boros unleashes his full power against Saitama, their clash tearing through the ship. As the fight progresses, Boros kicks Saitama to the moon. Back on Earth, Mumen Rider, Stinger, and Lightning Max evacuate the remaining survivors of City A. Tanktop Master hurls rubble at the ship, which Tatsumaki amplifies with projectiles. Having recovered, Bang crushes the final marble, ending Melzargard. Saitama rockets back from the moon, smashing into the ship and forcing it downwards. Boros channels a wo