Counter battles and Last Word

[M.Maddox]

If I were to play card X, and my opponent counterspells it, and I counterspell his counterspell with Last Word, can he play another counterspell targeting my original spell, X? Thanks.

[NoGameShow]

They're free to target you original spell all they want. Last Word is the only card that can't be countered and from your example hoping they don't respond you would win this particular counter war.

[Tacosnape]

Yes. They can do anything they want to your original spell.

[quicksilver]

This is why last word isn't so hot. It only allows you to stop your opponents spells, even if your opponent has a counter. It cannot force your own spells through around counters.