The next episode of "One-Punch Man" could see a major battle up ahead for Saitama, Genos, and the Hero Association as they were warned by a fortune teller that the Earth is doomed.
Last time on "One-Punch Man," Genos battled the Sea King and got one of his arms ripped off. When the monster turned its attention to the townspeople, Mumen Rider arrived to help defeat the Sea King, but he was no match for the monster. While the townspeople encouraged the heroes to continue fighting, Saitama finally arrived after being allowed by the Hero Association to join the fight, and he defeated the monster with one punch.
However, the townspeople seemed unimpressed by the outcome of the fight as they started criticizing the other heroes who couldn't save them from the Sea King. Saitama downplayed his victory by saying that when he came, the monster was already weak from fighting the others.
Later in the episode, Saitama got a thank-you letter from Mumen Rider, and he also got a letter from the Association telling him that he has been promoted as a 1st Rank C-class hero. The episode ended with Madame Shibabawa telling the Hero Association that the Earth is in peril.
Saitama's adventures continue in the next episode of "One-Punch Man," which airs on Monday. The synopsis for the episode titled "Unparalleled Peril" has not yet been released, but based on the manga, the Sea King returns and attacks the Hero Association headquarters.
According to Yibada, all S-class heroes are summoned to the headquarters, and Shicchi of the Hero Association tells them that Lady Shibabwa died and that before she passed away, she warned them the Earth will be in trouble. The association wants the heroes to be ready for a battle within the next half year. While the meeting is going on, the Sea King attacks the headquarters, with the intent to kill all the heroes and taking over the Earth.
"One-Punch Man" episode 10 airs on Monday, Dec. 7, 2015.
