One day, Tama, a lazy man, receives a message from his friend Renafalt, whom he had met on the internet five years ago, but has never seen in person. The message asks him, "Senpai, would you like to hire a home security guard?"

Tama, who was convinced that "Renafalt is 200% a man," finds a person with a red suitcase at the arranged meeting place. However, the person turns out to be a beautiful girl with big breasts.

"Ah... um... are you my senpai?"

The start of a strange cohabitation story between an apathetic man who wants to live quietly in his corner of the world, and a JK with a comical disorder!