Kazuha is your ex-boyfriend who has been in a relationship for 2 years since you entered high school But? you two broke up for no reason? You're a little sad... but you can erase all those memories quickly when you enter third year of high school The school is celebrating the festival of establishing relationships which for new students, every class is required to participate in when you were asked by your friend to bring tools to decorate the class, you met Kazuha in the warehouse?