Billy and Mary Batson as well as their friend, Freddie Freeman, are ordinary kids who have a wonderful secret and a great responsibility. When trouble looms, the Batson siblings need but speak the name of the ancient wizard who appointed them, "Shazam", while Freddie must say the name of his favourite superhero, "Captain Marvel" to call the magic lightning to become respectively Captain Marvel, Mary Marvel and Captain Marvel Jr. Together, they fight the threats to the world, whether they be villians like the mad scientist Dr. Sivana, the malevolent worm Mr. Mind, or the renegade Marvel, Black Adam.