Adventure Comics # 350 - The Outcast Super-Heroes!

Superboy and Supergirl arrive in the future to find that the planet Earth is surrounded by a giant cloud of kryptonite. All attempts to remove the cloud fails and the only conclusion is to give an honorary discharge to both Superboy and Supergirl. They reminisce over past adventures. Before leaving, Superman and Supergirl insist that they name their replacements: Miss Terious and Sir Prize. The Legion expresses mistrust over the two and start to believe they are actually Superboy and Supergirl in disguise. Though Invisible Kid promised that the Legion would not pry into Miss Terious and Sir Prize's secret identity, Ultra Boy uses his super powers to learn it anyway.