MHA:

Deku, Bakugo, and their other classmates are enjoying time alone in their dorms, when suddenly they're all falling. Next thing they know, they are on a strange island. It seems to be several years prior to their own time.

Creepypastas:

The Creepypastas are at the Slendermansion, when they took also fall and land at the island.

Miss Peregrine's Home for Peculiar Children:

Miss Peregrine is at the home with the children when she senses new people have entered her loop.

Which group do you want to start with?