Smokestack on the stack.

[serracollector]

My opponent has nothing in play but a smokestack with 4 counters on it.

I have in play two island and time vault and voltaic key. 

I declare smokestack on the stack, and in response tap my island to tap key to untap vault etc to take 2 turns.

Opponent says I can't, smokestack goes before I have a chance to respond.

Which is correct?

thank you.

[TheWhiteDragon]

the smokestack trigger (all opponent triggers) goes on the stack before your own triggers can resolve or before you can respond with instants....but your opponents triggers don't resolve until you have time to do all kinds of stuff at instant speed.  Same as how when he has a tangle wire, you can have the wire trigger go on the stack, tap your mana, then hurkyll's him before you actually have to tap anything (though you will still have to tap since the trigger remains even after the wire is gone).

And for the record, the correct play is to untap vault by skipping your turn - forcing your opponent to sac his smokestack on their turn (since you skip yours - including your upkeep) while you lose nothing and can then go infinite when the turn gets passed back to you.

[serracollector]

Indeed.  I feel silly about that game now.  Ty, I thought so.