When Will You Learn?

Oracle Text

When you set this scheme in motion, each opponent exiles the top card of their library. You may cast any number of nonland cards exiled this way without paying their mana costs.

Card Rulings

6/13/2017 If you cast a card “without paying its mana cost,” you can’t choose to cast it for any alternative costs, such as emerge costs. You can, however, pay additional costs. If the card has any mandatory additional costs, such as that of Tormenting Voice, you must pay those to cast the card.
6/13/2017 If the card has in its mana cost, you must choose 0 as the value of X when casting it without paying its mana cost.
6/13/2017 You must cast any of the exiled cards you wish to cast for free while this scheme’s ability is resolving. You can’t wait until later in the turn. Any cards not cast this way remain exiled for the rest of the game. The spells will be added to the stack in the order that you cast them.
6/13/2017 If the owner of one of the exiled cards leaves the game, that card leaves the game as well.
6/13/2017 Now you have learned.