After an outbreak of a new strain of pharyngoconjunctival fever, a group of students at boarding school are ordered to stay within the school facilities for two weeks at the beginning of summer vacation, as the virus may still be residing in their systems.

Touma Shin, one of the students forced to remain at school, soon finds himself cast out of his room in the dead of night over something petty. Wandering around the campus in attempt to calm his nerves, he is suddenly threatened by a mysterious gothloli girl brandishing a shovel.

Now, here's the thing - all of the girls being kept at the school come across as extremely young in terms of both physical appearance and height. What exactly is the meaning behind this? Well, the answer will become clear in due time...