Jin Taitai didn't expect that something would happen if he didn't wear eyeglasses while taking a bath, but his underwear had a hole in it and he couldn't wear it anymore. He threw it in the trash can, but because of his short-sightedness, he misjudged it and threw it into the bucket where other students put clothes.
What a coincidence that the owner of that bucket is a senior and the president of the student union!
Oh my god, senior, I was wrong!