Astronomers detect a giant asteroid heading toward Z-City. The Hero Association calls the S-Class heroes to stop it. At the Z-City Hero Association branch, Genos meets Bang, who explains the situation. Genos then leaves to stop the meteor.
Genos is seen speeding over rooftops and notices the citizens have already given up on their lives and activates his suitcase that reviles his new Arms Mode. As he prepares himself, Metal Knight flies by and lands on a rooftop, while Genos wonders if Metal Knight came to risk his life for the city, Metal Knight simply explains that it's just a suit and he's at a safe distance. Metal Knight simply came to test the new missiles he developed, then fires missiles from his back, with Genos complaining to himself that he can't fire his beam.
The missiles hit the meteor and Genos is amazed by the destructive power of those missiles, even when they could not stop the meteor. Genos' mind starts racing about how to destroy the meteor when Bang appears, but can not do anything as he is a close-range combatant. Genos thinks of Saitama and comes back to his senses. He opens up his chest to reveal his Power Core, which he attaches directly into the shoulder of his left arm. He tells Bang to get down and then launches a massive attack at the meteor. His attack does nothing to the meteor, unfortunately, and Genos runs out of power and collapses on the roof.
Suddenly, Saitama arrives and tells Bang to take care of Genos as he launches himself towards the meteor, destroying the building. As Saitama is flying he punches himself through the meteor, completely destroying it. The pieces of the meteor then start to rain on Z-City, destroying much of it. Saitama then lands, looks around, and nonchalantly states that the job is settled.
Three days after the meteor incident, the heroes rise in rankings. Genos is promoted to S-Class rank 16, Metal Knight is promoted to S-Class rank 6 and Saitama is promoted from C-Class rank 342 to C-Class rank 5. Even though Z-City was severely destroyed, no one died in the process.
- In the One-Punch Man: Hero Perfection databook, it is stated that the meteor was 200m (656'2").
- It took Saitama 8 seconds to destroy the meteor.