The Superheroes event, which will end on March 31st, is split into four (or five, technically) and revolves around the superheroes of Springfield defeating the evil criminals.
There will be four prize tracks with three prizes in each track (part), as well as the return of the crafting system from last Halloween and the upgrading system from Clash of Clones and Halloween. Carbon Rods, Freeze Rays and Arbitrarium are currency, from what I can deduct from the files, and I believe the latter is used to upgrade the Superior Squad HQ, one of the main buildings in the event.
There’s been plenty of changes and new additions, so why don’t you check out the event article here to discover more, while us at Wikisimpsons try to get all the information possible for the event article?!
That’s it for now! Sorry there’s not much, but that’s basically all we’ve got!