"One Punch Man" episode 10 opened with a monster from the Terror Lizard Clan who was defeated by class S hero Tornado.
Watch "One Punch Man" episode 10 here. It is entitled "Unparalleled Peril."
The next scene featured Silver Fang showing off his Fist of Flowing Water, Crushed Rock technique to Saitama, Genos and another student in his dojo. Someone from the Hero Association arrived to let them know that all class S heroes are being summoned.
Atomic Samurai greeted the trio when they arrived in the Hero Association meeting room. Almost all of the class S heroes arrive for the emergency. However, class S rank 6 hero Metal Knight and rank 1 hero Blast were absent.
Afterwards, someone from Hero Association named Sitch explained to everyone why the class S heroes were being summoned. Lady Shibabawa, the seer died while predicting the future.
"One Punch Man" episode 10 revealed that the prophet left a note that revealed that the Earth is in trouble. Suddenly, the building started to shake.
It was caused by winged monsters sending energy blasts to the Hero Association office. They are led by the Sky King who was killed by an even more sinister five-headed alien monster from a massive spaceship.
The spaceship and the monster caused the spike of the destruction levels detected at Hero Association to 99.8%. Meanwhile, Saitama has already left the room to check out the spaceship featured in "One Punch Man" episode 10.
City A seemed to have been destroyed by gigantic bullets coming out of the spaceship. Atomic Samurai's disciple, Iaron, loses his arm in the battle with the five-headed monster, which was able to split into five bodies.
Atomic Samurai came to Iaron's rescue however the monster couldn't be eliminated by sword alone. The monster morphed into an even more powerful form and class S heroes band together to defeat it.
Saitama was able to infiltrate the spaceship and started destroying it from the inside in "One Punch Man" episode 10.
