Marie thinks that she is being used as a substitute fiancée for her lost sister Anastasia; due to her parents breaking her self-worth. In truth, she was the one the proposal was meant for; the sender had mixed up their names.

Kanata quiere ser un Drifter y conoce a Noir, que es una Magus sin recuerdos, se asocia con ella y descubre exactamente lo que hace falta para ser un Drifter.

Tras un encuentro fortuito con un autoproclamado domador de kaiju, un estudiante de preparatoria se ve arrastrado a un mundo de lucha contra mechas y monstruos.