The movie begins with Cleopatra angry over Julius Caesar's claim that Egypt is a primitive country. To prove him wrong, she decides to commission a magnificent palace for herself to be built in just three months.
The best architect of the land is given the contract, but things quickly turn sour when he is given such a small timeframe to work with. His solution is to simply build a palace made out of wood, but Cleopatra will hear none of it. With her reputation on the line, she decides to seek out the help of Asterix and his friend Obelix, who, thanks to their magic potion, possess superhuman strength.
Asterix and Obelix are initially unwilling to take on such a daunting task, but they soon find themselves agreeing after Cleopatra reminds them that, if they can complete the project in time, they will be considered the greatest builders in history.
The duo immediately sets to work and completes many of the major buildings in a matter of days. Along the way, they meet a number of interesting characters, including a group of slaves who help them in their mission.
However, things take a turn for the worse when Caesar, angry that Cleopatra may succeed in her endeavor, sends his own architects to sabotage the construction site. With the help of the slaves and their own wits, Asterix and Obelix are able to thwart Caesar's plans and finish the palace in record time.
In the end, Cleopatra is delighted with the finished product and thanks the duo for their hard work. Asterix and Obelix are celebrated as heroes and are awarded various medals and trophies. Caesar, meanwhile, is left to rue the day he thought he could best the Queen of the Nile.