Warning! SPOILERS for Superman and Lois season 2, episode 5, «Girl… You'll Be a Woman, Soon.»
Superman's adoption of a new Fortress of Solitude in Superman and Lois finally addresses a security mistake that was never fixed in Supergirlafter Lex Luthor managed to break into the secret stronghold. While Luthor was trapped in the Phantom Zone in Supergirl's series finale, it still seems strange that the Super Friends didn't take immediate steps to secure the location. However, this might explain why Superman had a drastically different Fortress in Superman and Lois season 1, which did not resemble the Fortress of Solitude depicted in Supergirl.
The Superman and Lois season 2 episode «Girl… You'll Be a Woman, Soon» focused upon Superman's efforts to track his bizarre doppelganger from another dimension, who had killed two members of the Supermen of America. Superman captured the strange visitor from another world, but he had no easy way of containing him or learning more about him. His Fortress of Solitude was unavailable, having lost the artificial intelligence of Jor-El which powered it. He also couldn't turn to the Department of Defense for help, having lost the trust of the officer who was put in charge after General Sam Lane retired.
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Ultimately, Superman elected to make use of the Fortress created by his half-brother Morgan Edge (aka Tal-Rho) and a newly discovered artificial intelligence based on his mother, Lara Lor-Van. This allowed Superman to confirm the other-dimensional origins of the so-called Bizarro Superman and communicate with him, learning that he was on a mission to save his Bizarro World and Earth-Prime. Beyond being a brilliant
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