In player order, each player chooses a card to be sacrificed (a character or a location). Then, all chosen cards are sacrificed simultaneously (see Priority of Simultaneous Resolution).
Since this card doesn't use the word "choose" (so it's a non-targeting ability), you can play it even if one of the players has nothing to sacrifice (unlike Even Handed Justice).
If a player chooses to sacrifice a character that has Marriage Pact attached, the forced interrupt triggers after all choices are made but before the chosen cards are sacrificed. The Pact's controller may then choose to sacrifice the same character that he has already chosen to sacrifice for The North Remembers, and end up sacrificing only one card for both effects.
- You can sacrifice The God's Eye, but you cannot sacrifice Pleasure Barge.