In a world were everyone gets a voodoo doll based on their soulmates.

Katsuki had gotten a doll that almost exactly depicted one of his classmates...he didn't think much of it, so he tossed it in his bag and went to school. When he arrived, he took his seat at his desk. That's when he decided to test the doll out, due to the fact that his apparent soulmate, is his classmate who sits in front of him. Katsuki set the doll on his desk, he poked its side to see if he could get a reaction.