A global pharmaceutical company needs to collect data on the rectums and anuses of young people for clinical trials of a new drug that has revolutionary effects on rectal cancer. In return for a huge donation, the president of a co-educational school agrees to conduct anal health examinations on students. It is not hard to imagine that this would become sensational news if it were made public. In order to keep it more secret, it is decided to conduct it with both boys and girls, and to force the homeroom teacher to participate. The students are offered a carrot as a bait for recommendation to enter the school by improving their school grades. The female teacher is mind-controlled by being told to be a role model for her students as an educator, and thus a mixed-gender anal health examination is conducted.