The Muses tell the audience a story of the hero, Hercules.
One day, in Mount Olyumpus, the Greek gods and goddesses are celebrating the birth of Zeus and Hera's son, Hercules. Just then, Hades, the Lord of the Underworld, is not happy about it and is jealous of Zeus ruling everything that he wishes to overthrow him.
In the underworld, Hades gets into contact with the Fates, who tell him of a history that in 18 years later, the Titans, whom Zeus imprisoned, will be free and cause chaos. Unfortunately, there is only one who can stop them and is Hercules. Hades gets enraged by that kid of news.
He takes his two henchmen, Pain and Panic, to a chamber and asks them how to kill a god. They reply that they can kill a god if he/she is not immortal. Hades gets a potion and orders them to give Hercules a douse of it.
In the night at Mount Olympus, the baby Hercules gets abducted by Pain and Panic and they take him to the mountains. They give him the douse of the potion, but is not finished. Because of this, Hercules uses his strength to throw Pain and Panic off. The latter fears that Hades will get mad that they failed, but the former convinces him not to worry because he doesn't know about it. A farmer and his wife decided to adopt Hercules as their son.
Back at Mount Olympus, Zeus and Hera are saddened by the news of their son being abducted.
18 years later, Hercules is shown going to a marketplace with the farmer. However, his strength leads him to accidentally knocking the place and the people are not liking it.
At the afternoon, Hercules asks his foster parents about where he truly belongs and they give him a medallion he has since he was a baby. In the night, he goes to the Temple of Zeus. Upon going there, a statue of Zeus comes to life and is happy to be reunited with Hercules. He gets his him reunited with his pet horse, Pegasus and tells him that in order to be with him and the other gods and goddesses, he must be a hero trained under Philoctetes.
The next morning, Hercules goes to an island where he met Philoctetes, or Phil for short. He orders to be trained, but Phil refuses because he retires. Upon being told that Hercules' father is Zeus, Phil still refuses to train, but is struck by lightning by Zeus, giving him no other choice.
After training him, Hercules and Phil go to a forest where they see a woman named Meg getting into trouble with a centaur named Nessus. He beats him up and begins to fall in love with her, much to the dismay from Phil and Pegasus.
Meg meets up with Hades, and it is revealed that she sold her soul to him in order to be with the man she loved, but he left her with another woman. He asked her who beat Nessus up, and she replies that it is Hercules who done it. Hades is angered that Pain and Panic are hiding the truth from him and swears to get him so that he can't stop the Titans.
In the city of Thebes, Hercules tries to get respect from the people, but to no avail. Just then, a monster known as the Hydra comes and Hercules fights it. He defeats it and is respected by everyone, angering Hades in the process.
Since then, Hercules is treated as a celebrity thanks to Hades keep sending him monsters to defeat him.
Hades is getting irritated by this and orders Meg to find Hercules' weakness. In the night, Zeus tells Hercules that even though he is treated as a celebrity, he is not a true hero.
One night, Hercules and Meg are on a date when Phil and Pegasus interrupt in order to get the former trained. While trying to get Hercules to focus, he is knocked out.
After getting a flower, Meg tries to deny that she is falling in love with Hercules, but the Muses encourage her to admit her true feelings. Just then, Hades arrives to remind Meg that she works for him and has found out Hercules' weakness. Phil wakes up to find out Meg's secret and runs to warn Hercules.
In a coliseum, he tries to warn Hercules about Meg, but he refuses to believe such fact. When he throws a dumbbell to Phil, he leaves. Just then, Hades appears and shows Hercules that he has captured Meg and the only way to let her go is to make a deal of losing his powers for 24 hours. Hercules reluctantly agrees, but on one condition that Meg must not be harmed. After losing his powers, Hades throws a dumbbell at Hercules and decided to show him his secret about Meg.
He releases her, telling her that she is off with him. Hades reveals to Hercules that Meg is working for him all this time, but he thinks that he is lying. That is, until Pain and Panic has confirm it to him. Meg tries to apologize, but Hercules is saddened by her treachery.
Hades goes to the river to release the Titans and orders them to kill Zeus. When they are going the wrong way, Hades shows the Titans the way to Mount Olympus, and orders one of the the Cyclops to get rid of Hercules.
In the city of Thebes, the Cyclops causes chaos through town in order to lure Hercules into a trap. Hercules goes to confront him, but Meg warns him that without his strength, he will be killed. Hercules refuses to listen to her and goes to confront the Cyclops, which resulting in getting himself beaten up.
Meanwhile, the Titans has defeated the gods and goddesses.
Meg frees Pegasus and tries to convince Phil to go and help Hercules. She admits that it is all her fault that he lost his powers and persuades Phil to help because if he doesn't, Hercules will die.
Zeus orders to get more thunderbolts, but is captured and discovers that Hades is behind the entire plot.
Phil arrives to encourage Hercules to fight back. He fights the Cyclops with his brains and defeats him. When a pillar is about to fall on him, Meg gets in the way, only for her to get crushed. This results in Hades' deal to be broken and Hercules getting his powers back.
He goes to Mount Olympus to defeat the Titans. However, Hades tells him that Meg will be killed by the crushing of the pillar. By the time Hercules goes to her, she dies. However, Hercules states that he can save her.
In the underworld, Hades is angered that Hercules has foiled his plot. Just then, Hercules arrives and orders his uncle to get Meg back. Hades shows him the River Styx, a river where the souls of the dead are. When Hercules tries to get Meg's soul, his hands suddenly ages.
Hercules makes a deal with Hades that he will give up his own life to save Meg. He manages to save her, and because of his sacrifice, he becomes a god. He punches Hades to the river and the souls began to torment him. Panic is so afraid about getting into trouble, but Pain convinces him that there is nothing to worry as long as Hades is in the river.
Hercules gets Meg's soul back to her body, reviving her. He, along with his friends, go to Mount Olympus where he is reunited with the gods and goddesses, including his father and mother. Because Meg is sad about leaving her, Hercules decided to stay on Earth to be with her.
Upon going to the city of Thebes, Hercules is reunited with his foster parents and Zeus creates a constellation of him, symbolizing Phil's dream of creating a true hero.