If the target card is no longer in the graveyard when Cremate tries to resolve, it won't resolve and none of its effects will happen. You won't draw a card.
01-10-2012
wotc
You must be able to target a card in a graveyard to cast Cremate.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.