Clark has already been a hero for 10 years, in a stable relationship with Lois Lane and everything he could want for himself. But, he lacks something, a meaning for his actions and his interference with humanity, and with the arrival of U-Ban, Kizo and Mala, 3 survivors from ancient Krypton, Clark must reconnect with his Earthling and Kryptonian origins, to reach conclusion of what kind of hero and inspiring role model he wants to be.
The 3 Kryptonians would have the objective of becoming the leaders of Earth, trying to persuade Superman to become part of an empire of superiority, a proposal that Clark would obviously refuse. As Superman wouldn't stand a chance against 3 at once, he would have to separate them using their own egos and ambitions to create internal disputes, to be able to beat them separately, and send them to the Phantom Realm as instructed by the teachings of the hologram of Jor El in the Fortress of Solitude.
The film would address a lot about the issue of Kryptonian society being unempathetic and snobbish, and the 3 would be a portrait of that, and how the humble upbringing of the good people of Smallville shaped Clark to be the generous hero he is, and remember the example of kindness and generosity that he can inspire, is what was needed for him to fill the void in his life, the greatest gift of being a hero is to save and inspire.
