If an instant or a card with flash is plotted this way, you can still cast it only when you have priority during your main phase while the stack is empty.

Exiling a card using its plot ability is a special action. Once you announce you're taking that action, no other player can respond by trying to remove that card from your hand.

If a plotted card has {X} in its mana cost, you must choose 0 as the value of X when casting it without paying its mana cost.

If the copied spell divides damage or distributes counters among a number of targets, the division and number of targets can't be changed. If you choose new targets, you must choose the same number of targets.

If the game is restarted (by Karn Liberated), you can't cast Jace Reawakened in your first, second, or third turn in the new game.

If the spell that's copied has an X whose value was determined as it was cast, the copy will have the same value of X.

If the spell that's copied is modal (that is, it says "Choose one —" or the like), the copy will have the same mode or modes. You can't choose different ones.

If you're casting a plotted card from exile without paying its mana cost, you can't choose to cast it for any other alternative costs. You can, however, pay additional costs, such as kicker costs. If the plotted card has any mandatory additional costs, those must still be paid to cast the spell.

Jace Reawakened cares about how many turns you have taken, not necessarily how many turns the game has had, in case you take an extra turn.

Plot abilities are written "Plot [cost]," which means "Any time you have priority during your main phase while the stack is empty, you may pay [cost] and exile this card from your hand. It becomes plotted."

The copy created by Jace Reawakened's last ability will have the same targets as the spell it's copying unless you choose new ones. You may change any number of the targets, including all of them or none of them. The new targets must be legal.

The copy made by Jace Reawakened's last ability is created on the stack, so it's not "cast."

You can cast Jace Reawakened during another player's first, second, or third turns of the game if some other effect (such as Vedalken Orrery) enables that.

You can't cast a plotted card on the same turn it became plotted. On any future turn, you may cast that card from exile without paying its mana cost during your main phase while the stack is empty.

You can't choose to pay any additional costs for the copy. However, effects based on any additional costs that were paid for the original spell are copied as though those same costs were paid for the copy too.