Before the start of the nuclear war, covert attacks were made between countries/power blocks with terrorists as a front. One of these involved the detonation of a viral weapon in the sewers of Washington DC, causing the US to move its seat of power temporarily to New York. During this time the Russians sent a massive robot described as a giant hovering, burrowing woodlouse to attack NY. It was hoped that this would allow a swift takeover. Needless to say that it failed, and the first nuclear strikes occurred shortly after. New York, having been completely destroyed by the machine, is not nuked, but is still razed. The machine burrows into the ground and goes to sleep.
Fast forward to a period some years after Terra, relics of incredible power, the great bars of cursed lead, important relics to the mage’s college of Noyirk (unsurprisingly built on the ruins of old New York) have been stolen by the descendants of the forty-something technicians who travelled with the machine (called the ‘Lorica’), who need the bars to power the machine again (the bars are actually hyper-refined uranium). The rest is spoilers.
Things I want to add that need your approval:
-Noyirk is a large city, and likely the furthest south on the formerly American continent.
-there is a massive laser-firing satellite, maintained by cultists who are the descendants of those engineers who designed it. The re-powering shuttle designed to take the power cores required is totally automated. The markerlights required to target the satellite look like wands, and are used exclusively by sun mages, one of the disciplines of magic.
-miraculous are incredibly rare individuals, the results of the descendants of a military experiment to create nigh-immortal individuals.