Rule 719.5

At the end of a subgame, each player takes all cards they own that are in the subgame other than those in the subgame command zone, puts them into their main-game library, then shuffles them. This includes cards in the subgame's exile zone. Except as specified in rules 719.5a-d, all other objects in the subgame cease to exist, as do the zones created for the subgame. The main game continues from the point at which it was discontinued: First, the spell or ability that created the subgame finishes resolving, even if it was created by a spell card that's no longer on the stack. Then, if any main-game abilities triggered while the subgame was in progress due to cards being removed from the main game, those abilities are put onto the stack. Example: If a card was brought into the subgame either from the main game or from outside the main game, that card will be put into its owner's main-game library when the subgame ends.

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