Only on the second reading do I remember that one of them can't be there, because he's still trudging back from dealing with another wizard.
And while there is a third young man, I haven't mentioned that he's ever picked up a sword. So I go back and put in a scene where he's talking to the one who could be there, and practicing the sword.
Only after all that did I remember that I was going to have him fighting in a scene coming up very soon now.
Ah the delights of a multi-threaded story.