Then do it after a couple of seasons of not having any time travel, and find a decent way to do it. I would guess you mean Balance of Terror, but why? It's such a terrific episode in it's own right, why would you want anyone from another time messing about with one of the better tactical victories for the Federation? Are you anti-Kirk, hoping that only an intervention from the future could have caused the victory and it was due very little to Kirk's abilities? I'm very anti messing with Balance of Terror, I think. Besides, how will they explain the non-ridge headed Romulans (you know, Romulans the way they are supposed to be, not the really lame ones)?