Herculopolis High (サタンシティのハイスクール, Satan Shiti no Hai Sukūru; lit. "Satan City's High School") is the four hundred twenty-first chapter of the Dragon Ball manga.
The chapter begins with a synopsis of the events happening after the battle with Cell. With Goku's sacrifice, the Earth and its people could live again in peace. Mr. Satan was now the believed savior of the world, and a city was established in his honor, where millions of peaceful Earthlings were living.
A group of criminals were shown robbing a bank, promising to return once they've spent the money. Now 16 years old (18 in the anime as he was 11 when fighting Cell), Gohan is shown riding the Flying Nimbus to his first day of high school at Orange Star High School in Satan City. After the past 7 years of homestyle tutoring, Chi-Chi believed this was growing insufficient, as there was no school where they lived.
Telling goodbye to the Flying Nimbus until after school, Gohan landed in Satan City. Noticing he was late, he looked around to see if anyone was watching, then proceeded to run full-speed toward school, surprising a couple driving a car past him. Gohan then noticed the commotion going on at the bank being robbed. Gohan then decided to do something about the robbery and transformed into a Super Saiyan to hide his identity. Gohan single-handedly eliminated the robbers, effortlessly catching a round of bullets from the gun a robber was firing at him. The remainder of the robbers tried to flee in a truck, prompting Gohan to use a Kiai to knock the truck over. When the police finally arrived to the scene, they found the defeated robbers and wondered what happened.
Videl appeared behind Gohan and asked him what happened, as the police could not have done something like this. Saying he didn't see anything, Gohan secretly fled from the scene while a man told Videl that the Golden Warrior (Gohan's nickname as a Super Saiyan) was responsible. The man then told Videl that the Golden Warrior also attended Orange Star High School, as their school badges are the same. Videl then wondered who went to her school that had golden hair.
Later at Orange Star High School, Videl asked Sharpner if he was the Golden Warrior, who declined stating he was too busy exercising to defeat some robbers. As Erasa commented that the Golden Warrior may be stronger than Mr. Satan, the teacher introduced Gohan as the new student in the class. Secretly calling Gohan handsome, Erasa welcomes Gohan to an empty seat next to her, and introduces Gohan to Videl, stating she is Mr. Satan's daughter, which shocks Gohan.