We open to a wedding feast atop Mount Olympus. Of all the gods only one was left uninvited to the feast. This was Eris, who had only been left off by accident.
A furious Eris, having been left off the guest list, gets revenge by rolling a golden apple bearing an inscription of “to the fairest” into the feast hall. Athena, Aphrodite, and Hera all claim the prize.
Zeus tells Hermes to go and find an impartial judge to settle the matter, and Hermes returns with the young Prince Paris. Each goddess offers him a reward for his vote, Athena, victory, Hera, the world, and Aphrodite, the most beautiful woman. He chose Aphrodite, and thus was rewarded with Helens love.
Paris came to Greece to claim his prize, and found that Helen was the wife of the Greek king Menelaus. He wooed her anyway, and took her home to Troy in the night. Menelaus invoked the oath of Tyndareus, which was created by Odysseus to protect the future suitor of Helen, and raised an army to take her back from Troy.
After unsuccessfully besieging Troy for nearly a decade, Odysseus proposed an idea to take Troy and breach the walls. The Greeks created a great wooden horse and hid soldiers inside. They left the horse at the gate as though it were a gift.
The Greeks pretended to sail away, and the Trojans, believing they had been victorious in fending off the attackers, celebrated by drinking and partying. They took the horse into their city and when all the sound had died down and everyone was asleep, the soldiers left the horse and killed much of the city before anyone knew what was happening, thus taking the city.