Superman: Unbound

Superman and Supergirl team up to stop Brainiac, a cyborg scientist who collects knowledge by destroying entire planets. After being captured by Brainiac's drones, Superman breaks free and forces Brainiac to experience life outside of his artificial environments, leading to the villain's downfall. With the help of Supergirl and Lois Lane, Superman saves the world and even finds love with Lois, leading to a romantic marriage proposal at the end.