This is a picture of Shiragiku-san, who was on duty that day and was attending class in her bloomers when the bottom of the vase she was trying to change the water in fell out, soaking her skirt and tights, and then after class she bumps into someone in the classroom and falls, and when she looks up, her eyes are drawn to the white camisole peeking out from under her sailor uniform and her equally white thighs, and she is unable to move.