Zeus is the king of the gods, Hades is his brother and the god of the underworld. Cronus is their father, a titan. They live on Mount Olympus. The brothers are headed to a magical lake so that Zeus can tell Hades that he wants to have him back.
Cronus has a history of trying to get rid of his children. Now he wants to take over Mount Olympus and kick his children out. He is planning this.
Cronus attempts to talk Hades into joining him. Cronus spends time with Hades. Hades and Zeus argue but decide to work together after being told what Cronus is planning.
The war. Zeus and Hades win - they are going to give him a death sentences after he gives up, realizing that he is out numbered. During the fight, Hades gets severely hurt.
They apologize to the seer for doubting him. The gods and goddesses decide to banish Cronus to a hole in the earth so that he cannot try to overthrow them again. Hades decides to return to the underworld even though he is no longer banished.
Hades and Zeus are still friends and get together to fishing much more often. With the gods happy, they people below Mount Olympus are too.