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Historical Rules · 1 May 2011

Rule 704.5w

Official source text from the 1 May 2011 Rules release

In an Archenemy game, if a non-ongoing scheme card is face up in the command zone, and it isn't the source of a triggered ability that has triggered but not yet left the stack, that scheme card is turned face down and put on the bottom of its owner's scheme deck. See rule 904, "Archenemy."

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