At the beginning of your upkeep, exile the top card of each opponent's library. Until end of turn, you may cast spells from among those exiled cards, and you may spend mana as though it were mana of any color to cast those spells.
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Stolen Strategy doesnâ€™t change when you can cast the exiled card. For example, if you exile a sorcery card, you can cast it only during your main phase when the stack is empty.
If you donâ€™t cast the exiled cards, they remain exiled. They canâ€™t be cast on later turns.
Casting an exiled card causes it to leave exile. You canâ€™t cast it multiple times.