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.

Hanabi Ayase and her best friend, Yui Aoi, are 6th graders in school. When Hanabi is chosen to work with Yuuto Takao for an upcoming test, she begins to fall in love with him and they both start dating. Yui also falls in love with Kazuma Hiyama, after he protects her from a classmate who talked about Yui behind her back, and they start dating as well. But with physiological changes and more and more obstacles in their love lives, will Hanabi and Yui overcome everything and find true love at the age of 12?

Un joven se escapa hacia el mundo que se erige en la superficie y descubre una violenta tierra en la que humanos se enfrentan a robots controlados por un ambicioso noble.