Mary Marvel: A League of Monsters
by Libbylawrence, partially adapted from Superman #276 by Elliot S! Maggin and Curt Swan 
Summoned by an old medicine man who reminds her of the old wizard Shazam himself, Mary Marvel travels to a parallel Earth decades ago in the past, where she fights to save the counterparts of the Marvel Family from the clutches of the nefarious Monster League of Evil! But even if she succeeds in saving the Thunder Family — Captain Thunder, Mary Thunder, and Captain Thunder Junior — can she possibly also save their world from being eventually erased from existence in the Crisis on Infinite Earths?