Everyone gathered at North’s place, Tooth, Sandy, Bunny, and Jack. Everyone gathered because North told them that the man in the moon shines, that they’re having a new guardian with them

The rest is up to your story.

North: "Everyone! The man in the moon is choosing a new guardian!"

Bunny: "Now why this time!? We already have this frosty bite guy here! Haven’t we?!"

Jack: "Hey now, Peter Cottontail! We’re not here talking about me, we're here for a new guardian, and you’re not starting a complicated conversation with it?!"

North: "We’re not sure this time! But many think it is because of the children."

Tooth: "Are we having a new guardian Is it because of something special for the children that they love?!?"

Sandy: Using his sand powers to communicate "Hollowen?"

Bunny: "Halloween!? Sandy that’s impossible, hehe… Right?"