Does anyone know how the Night Hunt event works well enough to explain it to me?
You gradually gain Magic resource. Every now and then its consumed to generate some special event-only resource. To find the resource, you'll need to mouse-over the icon. In terms of where it shows up it can be seemingly in nearly any other place. a normal-icon will swap to event icon. For example Copper in mining, or a Gem in gems. Just go through your various tabs until finding it. It can even spawn on prestige sub-section apparently.
Icons it can be are something like "maple leaf", "grass", "skull", "clover", or a potion bottle thing.
Once you have some, you can attempt a ritual. These gives you points for event shop, can unlock potions and unlock a new resource for the event which so far I've only seen as able to combine multiple resources into potion, and higher chance to succeed.