While Sonic finds Saitama's apartment but has to deal with Genos, Blizzard, with her two subordinates Eyelashes and Wild Monkey, try to recruit Saitama, but he refuses. In the bonus chapter, King is targeted by a number of hitmen at a restaurant, but his actions lead them to think twice about attacking him. In another bonus chapter, Bang invites Saitama and Genos for hot pot but a gang tries to challenge the dojo and loses. Tank-Top Master also briefs Saitama on Garo's tactics, saying they are based on martial arts and are different from those of monsters. Deep Sea King attacks an evacuation shelter of civilians and finds less than a handful of minor superheroes including Snakebite Snek, who stall the monster until help arrives. Chlld Emperor develops a mask that assesses the power levels of heroes and monsters, but it is still a work in progress.
Meanwhile, Sitch is disappointed that the executives in the Hero Association would rather focus on giving hero names to Genos and Saitama and place minimal effort in going after Garo. Sonic also gives a try but realizes he needs a weapon and retreats. Saitama meets Charanko's old acquaintance Sour Face and learns the format of the tournament. In the bonus chapters, Saitama helps a little girl find her lost cat while Genos and other superheroes go after the Grizz-Meow. As none of them are able to stop it, Saitama comes in and shatters it into a bunch of fragments which damage the city but prevents a worldwide catastrophe. Genos goes outside to fight the Demon-level monsters nearby and receives support from the association as to their locations. Saitama advances to the finals and faces Suiryu, who tells him he would like the match to be fun.
A fierce-looking lead monster Goketsu announces his plan to convert the fighters into monsters. Although Melzargard hits Bang, Atomic Samurai chops up Melzargard, and Bang crushes Melzargard's last marble essence. Tornado blames Saitama for running around uncontrolled, but Bang tells them to stop. Tips: You're reading One Punch-Man 99. Carnage does not believe Saitama and tries to kill him, but is easily killed. A group of sea monsters called the attack City J.
The association gives her a day off, but she gets bored. In the bonus chapters, a large robot approaches the headquarters, and some heroes are deployed to stop it, but it turns out to be Metal Knight's reconstruction robots. Sonic challenges Saitama and uses his speed to make afterimages of himself, but Saitama counters with even more, knocking Sonic down with his side stepping. Their fight is interrupted by Sonic and Genos, who impress both with their speed, but Genos is defeated. The police bring in Saitama for questioning, but after offering him a pork cutlet bowl, Saitama defeats a monster that attacked the police station. For three years, Saitama won countless monsters, but no one knows about it.
The losing gang encounter Garo afterwards. Bang's disciple Charanko gives Saitama his contestant entry for a martial arts tournament. It's because he is not a hero registry Association! Blizzard tries to fight Saitama, but Saitama stops her, telling her that such newbie-crushing activity is pointless. The Sea King also defeats Lightning Max but then must face. Saitama realizes he has no visibility as a hero, so he is advised by Genos to join the Hero Registry as a professional hero in the Hero Association.
Metal Knight arrives to salvage ship parts to make weapons. Sonic thinks Saitama is a Paradiser and attacks him but is defeated when Saitama inadvertently hits his groin. He is placed in rank 1 and applies to advance to B-Class. Rhino defeats Pineapple and Mohican to abduct Narinki's son. Suiryu is beaten down and realizes he needs a hero after all, and cries for help. Saitama enters a hero costume contest, but lets a boy use his costume, and finds the contest judge to be very harsh on all the contestants.
Monsters continue to invade the cities including the hospital and the prison, with many of the S-Class heroes fighting them off as much as they can. Melzargard continues to regenerate and pose a problem to the heroes until they find his weakness is that he hides a marble essence in each of his heads. The ship crashes into the mostly destroyed A-City. Bang, on the other hand, takes the task of going after Garo seriously, and seeks his brother Bomb. He runs around the city looking for a villain but has no luck. The headquarters which survived the attack, is reconstructed into a fortress. Although slight costs start for that purpose, I do some shopping to you in comfort, and want you to enjoy the product.
More high-level monsters surface, causing havoc in all the cities. The bonus manga chapter has a story about 12-year-old Saitama in middle school and how he had to deal with some bullies and a piggy bank monster that took his 200 yen. The bonus chapter follows Sonic's imprisonment where he fends against some other prisoner thugs and then Puri-Puri Prisoner. That's because he isn't in the Hero Association's registry! As Genos moves into Saitama's apartment, Saitama discovers that C-Class members must do at least one heroic deed a week or they are dropped. He defeats the centipede, but then the Centisenpai attacks, and then Centichoro. A robot named G4 challenges King, who excuses himself to go to the restroom.
Bonus manga that are 1-2 page s long are not listed in index, all hidden bonuses are listed after chapter. In the other bonus chapter, a member of the B-Class heroes' subgroup takes on a formidable opponent. Mosquito Girl powers up and rips Genos apart but Saitama swats Mosquito Girl easily. Blizzard defends against being mind-controlled herself, and is saved by her sister Tornado. One of them offers Garo membership to their new Monsters Association. In the bonus chapter, Saitama encounters a suicidal worker while he's eating lunch. As heroes , Bang, Puri-Puri Prisoner, and try to fight Melzargard, a shape-shifting alien with five heads, the others try to figure out how to get to the spaceship, while Saitama has already punched his way in, defeating Groribas.