Adaterra

About 1000 years ago, a global arcane-thermonuclear war wiped out many cities and people on the planet. This war was caused by two powerful nations each trying to take over the world, siding against each other and destroying each other and much if the world. After the conflict, a few remaining powerful magic users banded together, and believing it was the technology that caused the destruction, enlisted the help of Kaecon and many Wish spells to revert the level of technology to medieval, especially all weapons. However, Kaecon added another effect - he wiped the minds of all the survivors, removing their specific memories of the war. He also sent out troops to kill the young of long-living races, so that after 1000 years no one would have lived through the war, even if they didn’t remember it due to the spell. Places where many nukes had been dropped were unlivable due to the levels of radiation, and after sickness and mutation people left them and called them “Cursed Zones,” since they did not remember radiation. After many years, the population grew and nations reformed. Technology grew back, but it grew differently - no guns, gunpowder or bombs, but yes printing presses, plumbing and light microscopes. Magic provides other things - magic communication towers as the telegram/internet, golems as industrial robots and flying ships as airplanes. (Some of those are more recent than others. Steam engines and teleportation circles have just been implemented at the start of the story, and flying ships only appear partway in.) 500 years after the war and 500 years before the start of the story, an inventor rediscovers radio waves and magically creates a device to hear it, then hears messages from a distant alien civilization. The inventor responds, but it takes 200 years for the message to reach them and another 200 for their reply to come back. The descendants of the inventor hear this message and learn that the aliens are coming to their world, and will be arriving in 100 years. One of their children is the Mayor of Censoma, who decides that the world needs to prepare for the alien’s arrival, but knowing about it would lead to mass panic. If the aliens are hostile, the world will need powerful weapons to fight them off. If the aliens are friendly, the world needs to present a united front to parlay with them. She tasks some of her secretaries with creating powerful weapons and others with orchestrating world peace (no biggie) and creating a global government. However, she needs an independent group of adventures to secretly implement policies and find knowledge, and when she hears of the attacks on the town she sets up the test quest. Her scientists and arcanists are working on weaponry and her diplomats and merchants are working on unification. The scientists discovered the atom recently, and with magic they quickly split it and discovered nuclear energy. No one knows that the old war was fought with nukes - not yet, anyway - so no one knows the devastation their creations can cause. Similarly, no one knows that the two great nations that started the old war were each trying to establish a global government of their own - just like Censoma is. This lack of knowledge could mean devastation, but even if they knew...what else can they do to prepare?