Captain Thunder. A mighty super-hero hailing from the Earth of a parallel dimension whose secret identity is that of young Willie Fawcett, an employee of WHAM-TV. One night, while on a Summer camping trip with a group of fellow orphans, Willie noticed a mysterious owl flying overhead, which seemed to beckon the youth to follow it. Pursuing the owl towards the solid rock wall of a hillside, the rock face suddenly opened into a cavern and Willie followed the owl inside and, to his astonishment, encountered Merokee, the last of the Mohegan tribe's great medicine men. Merokee explained that a tribal legend told of a boy of noble spirit would come forth and be invested with great powers by the last of the Mohegan shamans, and that Willie was the boy described in the legend. Holding up a belt with a lightining bolt emblazoned on its buckle, Merokee told Willie that, upon rubbing the buckle and speaking the word "Thunder", the boy would be invested with seven magical powers as follows: Tornado (power), Hare (speed), Uncase (bravery), Nature (wisdom), Diamond (toughness), Eagle (flight) and Ram (tenacity). Willie rubbed the buckle and spoke the magic word as instructed, and was instantly transformed by a brilliant starburst and a clap of thunder into the powerful hero called Captain Thunder. Proclaiming to the Great Spirit that his work was done and that he was ready to pass on, Merokee was transformed into a spirit and soared skyward, leaving Captain Thunder to do battle with the forces of evil whenever and wherever they arose.
Throughout the 1950s on his native Earth, Captain Thunder battled all manner of crimes and injustices across the globe, becoming that world's greatest hero. His greatest battles were against a coalition of incredible creatures known as the Monster League of Evil, whom he fought across 1,953 different dimensions and finally imprisoned in a misty purgatory-like realm. As Captain Thunder was leaving to return to his native dimension, the Monster Leaguers placed a curse on the Captain that would cause him to turn evil when next he assumed his heroic guise. Through some unknown mishap, Captain Thunder (in his Willie Fawcett identity) wound up in and alley of Metropolis on Earth-1 in 1974. When Willie witnessed a crime in progress, he transformed himself into Captain Thunder with the intent of capturing the criminals, but instead turned to evil as the Monster League had planned. Captain Thunder fought two titanic battles against Superman (proving himself to be a peer to the Man of Steel in sheer might), after which Thunder was forced by the Action Ace to use his wisdom to break the curse that the Monster League placed on him. Realizing that he was in the wrong dimension, Captain Thunder thanked Superman for his help and used the power of his magic word to return to his native universe (S No. 276/1, June 1974: "Make Way for Captain Thunder!").