No one would suspect that Airi Sezaki and Hinako Hanamura are close. They do not have the same social circle and rarely interact with one another during school. Little does anyone know that at the end of each day, the two rendezvous in an empty classroom and indulge in the unspeakable. It is within this room that Airi and Hinako can secretly share their mutual depravity. But these salacious meetings soon drag the girls into larger problems the deeper they dive into their fetishes.