The movie begins with Ptolemy I Soter narrating the key events of Alexander's life and events revolving around his invasion of the Achaemenid Empire (Persian Empire). He was declared a god in Egypt and then found the pivotal Battle of Gaugamela, where the Persian army was defeated and later fell. The story then goes back to show the strained relationship between Alexander's mother (Olympias) and Philip II. Alexander takes solace in wrestling, horse riding, and becomes tutored by Aristotle.
After Alexander is declared king and unites the Greeks, his campaign against the Persians commences. One key focus was on Alexander entering Babylon, one of the great cities of the Achaemenid (Persian) Empire. Alexander is depicted as being in awe of the great city and showed more interest in uniting the Persian world with the Greek world. While his soldiers delight in his great victory, Alexander is shown as thinking more about the future. He gives royal individuals to remain and be treated with respect. Meanwhile, while Alexander is staying in Babylon, his mother makes him aware of conspiracies against him but berates him for being too generous with his enemies .