I've read the rules, and there's no clear answer. I also think this card can be ridiculous. If a player casts a spell and {possibility storm} is on the battlefield, does that spell resolve? Or is it only the spell that is cast with the {possibility storm}.
The initial spell you play will be exiled, and will not resolve. It will then be shuffled back, along with all the other exiled cards
I knew it wouldnt take long for your response.
That's really ugly in an American control deck paired with {Curse of Exhaustion}