A Superman/Supergirl (Animated Movie) will be based from the #252 Action Comics on Superman released way back in 1958, that The Man of Steel, was to believe that he was the only survivor to his home planet krypton. Before his home planet was destroyed. Til then a surviving orbit of Krypton's core flew off into space for years, before he was born. He sees a teenage girl dressed in the blue and red outfit similar to his. Wearing a cape and a skirt. She introduce herself to her cousin Kal-El and say "Hey! Superman I have all your powers". Her name is Kara as Jor-El's niece. I think the Origin of Superman from the "Justice League: New Frontier" film, should be used for the upcoming Superman/Supergirl (animated movie). How does that sound ?