Situation dependent but it breaks down like this, if you have a T3 and Narset and cast Day's Undoing on their draw step after they draw a card for turn they get 0 cards after resolution. If the Day's Undoing is cast on your turn with Narset the opponent gets 1 card.
Day's undoing exiles itself
What a beatiful deck btw. I'm waiting for the banlist and see what to play, but this control is great
He didn't draw seven after the days undoing?
Narset, Parter of Veils sure is a messed up card
Situation dependent but it breaks down like this, if you have a T3 and Narset and cast Day's Undoing on their draw step after they draw a card for turn they get 0 cards after resolution. If the Day's Undoing is cast on your turn with Narset the opponent gets 1 card.